diff --git a/lib/address.js b/lib/address.js
index 88c8616..b7e3ec5 100644
--- a/lib/address.js
+++ b/lib/address.js
@@ -17,6 +17,8 @@ var JSUtil = require('./util/js');
  * An address has two key properties: `network` and `type`. The type is either
  * `Address.PayToPublicKeyHash` (value is the `'pubkeyhash'` string)
  * or `Address.PayToScriptHash` (the string `'scripthash'`). The network is an instance of {@link Network}.
+ * You can quickly check whether an address is of a given kind by using the methods
+ * `isPayToPublicKeyHash` and `isPayToScriptHash`
  *
  * @example
  * ```javascript
@@ -40,6 +42,8 @@ var JSUtil = require('./util/js');
  * @constructor
  */
 function Address(data, network, type) {
+  /* jshint maxcomplexity: 12 */
+  /* jshint maxstatements: 20 */
 
   if (!(this instanceof Address)) {
     return new Address(data, network, type);
@@ -49,6 +53,11 @@ function Address(data, network, type) {
     return Address.createMultisig(data, network, type);
   }
 
+  if (data instanceof Address) {
+    // Immutable instance
+    return data;
+  }
+
   if (!data) {
     throw new TypeError('First argument is required, please include address data.');
   }
@@ -61,24 +70,7 @@ function Address(data, network, type) {
     throw new TypeError('Third argument must be "pubkeyhash" or "scripthash".');
   }
 
-  var info;
-
-  // transform and validate input data
-  if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 20) {
-    info = Address._transformHash(data);
-  } else if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 21) {
-    info = Address._transformBuffer(data, network, type);
-  } else if (data.constructor && (data.constructor.name && data.constructor.name === 'PublicKey')) {
-    info = Address._transformPublicKey(data);
-  } else if (data.constructor && (data.constructor.name && data.constructor.name === 'Script')) {
-    info = Address._transformScript(data, network);
-  } else if (data instanceof Address) {
-    return data;
-  } else if (typeof(data) === 'string') {
-    info = Address._transformString(data, network, type);
-  } else {
-    throw new TypeError('First argument is an unrecognized data format.');
-  }
+  var info = this._classifyArguments(data, network, type);
 
   // set defaults if not set
   info.network = info.network || Networks.get(network) || Networks.defaultNetwork;
@@ -102,17 +94,37 @@ function Address(data, network, type) {
   return this;
 }
 
+/**
+ * Internal function used to split different kinds of arguments of the constructor
+ * @param {*} data - The encoded data in various formats
+ * @param {Network|String|number} [network] - The network: 'livenet' or 'testnet'
+ * @param {String} [type] - The type of address: 'script' or 'pubkey'
+ * @returns {Object} An "info" object with "type", "network", and "hashBuffer"
+ */
+Address.prototype._classifyArguments = function(data, network, type) {
+  /* jshint maxcomplexity: 10 */
+  // transform and validate input data
+  if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 20) {
+    return Address._transformHash(data);
+  } else if ((data instanceof Buffer || data instanceof Uint8Array) && data.length === 21) {
+    return Address._transformBuffer(data, network, type);
+  } else if (data.constructor && (data.constructor.name && data.constructor.name === 'PublicKey')) {
+    return Address._transformPublicKey(data);
+  } else if (data.constructor && (data.constructor.name && data.constructor.name === 'Script')) {
+    return Address._transformScript(data, network);
+  } else if (typeof(data) === 'string') {
+    return Address._transformString(data, network, type);
+  } else {
+    throw new TypeError('First argument is an unrecognized data format.');
+  }
+};
+
 /** @static */
 Address.PayToPublicKeyHash = 'pubkeyhash';
-/**
- * @static
- * @value 'scripthash'
- */
+/** @static */
 Address.PayToScriptHash = 'scripthash';
 
 /**
- * Internal function to transform a hash buffer
- *
  * @param {Buffer} hash - An instance of a hash Buffer
  * @returns {Object} An object with keys: hashBuffer
  * @private
@@ -130,7 +142,7 @@ Address._transformHash = function(hash){
 };
 
 /**
- * Internal function to discover the network and type
+ * Internal function to discover the network and type based on the first data byte
  *
  * @param {Buffer} buffer - An instance of a hex encoded address Buffer
  * @returns {Object} An object with keys: network and type
@@ -138,24 +150,21 @@ Address._transformHash = function(hash){
  */
 Address._classifyFromVersion = function(buffer){
   var version = {};
-  switch(buffer[0]){ // the version byte
+  version.network = Networks.get(buffer[0]);
+  switch (buffer[0]) { // the version byte
     case Networks.livenet.pubkeyhash:
-      version.network = Networks.livenet;
       version.type = Address.PayToPublicKeyHash;
       break;
 
     case Networks.livenet.scripthash:
-      version.network = Networks.livenet;
       version.type = Address.PayToScriptHash;
       break;
 
     case Networks.testnet.pubkeyhash:
-      version.network = Networks.testnet;
       version.type = Address.PayToPublicKeyHash;
       break;
 
     case Networks.testnet.scripthash:
-      version.network = Networks.testnet;
       version.type = Address.PayToScriptHash;
       break;
   }
@@ -172,6 +181,7 @@ Address._classifyFromVersion = function(buffer){
  * @private
  */
 Address._transformBuffer = function(buffer, network, type){
+  /* jshint maxcomplexity: 9 */
   var info = {};
   if (!(buffer instanceof Buffer) && !(buffer instanceof Uint8Array)) {
     throw new TypeError('Address supplied is not a buffer.');
@@ -198,7 +208,7 @@ Address._transformBuffer = function(buffer, network, type){
 };
 
 /**
- * Internal function to transform a PublicKey
+ * Internal function to transform a {@link PublicKey}
  *
  * @param {PublicKey} pubkey - An instance of PublicKey
  * @returns {Object} An object with keys: hashBuffer, type
@@ -215,7 +225,7 @@ Address._transformPublicKey = function(pubkey){
 };
 
 /**
- * Internal function to transform a Script
+ * Internal function to transform a {@link Script} into a `info` object.
  *
  * @param {Script} script - An instance of Script
  * @returns {Object} An object with keys: hashBuffer, type
@@ -235,9 +245,13 @@ Address._transformScript = function(script, network){
 /**
  * Creates a P2SH address from a set of public keys and a threshold.
  *
- * @param {Array} publicKeys
- * @param {number} threshold
- * @param {Network} network
+ * The addresses will be sorted lexicographically, as that is the trend in bitcoin.
+ * To create an address from unsorted public keys, use the {@link Script#buildMultisigOut}
+ * interface.
+ *
+ * @param {Array} publicKeys - a set of public keys to create an address
+ * @param {number} threshold - the number of signatures needed to release the funds
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @return {Address}
  */
 Address.createMultisig = function(publicKeys, threshold, network) {
@@ -248,8 +262,8 @@ Address.createMultisig = function(publicKeys, threshold, network) {
 /**
  * Internal function to transform a bitcoin address string
  *
- * @param {String} data - An instance of PublicKey
- * @param {String} [network] - The network: 'livenet' or 'testnet'
+ * @param {String} data
+ * @param {String|Network} [network] - either a Network instance, 'livenet', or 'testnet'
  * @param {String} [type] - The type: 'pubkeyhash' or 'scripthash'
  * @returns {Object} An object with keys: hashBuffer, network and type
  * @private
@@ -266,8 +280,8 @@ Address._transformString = function(data, network, type){
 /**
  * Instantiate an address from a PublicKey instance
  *
- * @param {PublicKey} data - An instance of PublicKey
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {PublicKey} data
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @returns {Address} A new valid and frozen instance of an Address
  */
 Address.fromPublicKey = function(data, network){
@@ -280,7 +294,7 @@ Address.fromPublicKey = function(data, network){
  * Instantiate an address from a ripemd160 public key hash
  *
  * @param {Buffer} hash - An instance of buffer of the hash
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @returns {Address} A new valid and frozen instance of an Address
  */
 Address.fromPublicKeyHash = function(hash, network) {
@@ -292,7 +306,7 @@ Address.fromPublicKeyHash = function(hash, network) {
  * Instantiate an address from a ripemd160 script hash
  *
  * @param {Buffer} hash - An instance of buffer of the hash
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @returns {Address} A new valid and frozen instance of an Address
  */
 Address.fromScriptHash = function(hash, network) {
@@ -304,7 +318,7 @@ Address.fromScriptHash = function(hash, network) {
  * Instantiate an address from a Script
  *
  * @param {Script} script - An instance of Script
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @returns {Address} A new valid and frozen instance of an Address
  */
 Address.fromScript = function(script, network) {
@@ -316,7 +330,7 @@ Address.fromScript = function(script, network) {
  * Instantiate an address from a buffer of the address
  *
  * @param {Buffer} buffer - An instance of buffer of the address
- * @param {String} [network] - The network: 'livenet' or 'testnet'
+ * @param {String|Network} [network] - either a Network instance, 'livenet', or 'testnet'
  * @param {String} [type] - The type of address: 'script' or 'pubkey'
  * @returns {Address} A new valid and frozen instance of an Address
  */
@@ -329,7 +343,7 @@ Address.fromBuffer = function(buffer, network, type) {
  * Instantiate an address from an address string
  *
  * @param {String} str - An string of the bitcoin address
- * @param {String} [network] - The network: 'livenet' or 'testnet'
+ * @param {String|Network} [network] - either a Network instance, 'livenet', or 'testnet'
  * @param {String} [type] - The type of address: 'script' or 'pubkey'
  * @returns {Address} A new valid and frozen instance of an Address
  */
@@ -361,19 +375,19 @@ Address.fromJSON = function fromJSON(json) {
  *
  * @example
  * ```javascript
- *
- * var error = Address.getValidationError('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'testnet');
  * // a network mismatch error
+ * var error = Address.getValidationError('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'testnet');
  * ```
  *
  * @param {String} data - The encoded data
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @param {String} type - The type of address: 'script' or 'pubkey'
  * @returns {null|Error} The corresponding error message
  */
 Address.getValidationError = function(data, network, type) {
   var error;
   try {
+    /* jshint nonew: false */
     new Address(data, network, type);
   } catch (e) {
     error = e;
@@ -386,13 +400,11 @@ Address.getValidationError = function(data, network, type) {
  *
  * @example
  * ```javascript
- *
- * var valid = Address.isValid('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'livenet');
- * // true
+ * assert(Address.isValid('15vkcKf7gB23wLAnZLmbVuMiiVDc1Nm4a2', 'livenet'));
  * ```
  *
  * @param {String} data - The encoded data
- * @param {String} network - The network: 'livenet' or 'testnet'
+ * @param {String|Network} network - either a Network instance, 'livenet', or 'testnet'
  * @param {String} type - The type of address: 'script' or 'pubkey'
  * @returns {boolean} The corresponding error message
  */
@@ -428,7 +440,7 @@ Address.prototype.toBuffer = function() {
 };
 
 /**
- * @returns {Object} An object of the address
+ * @returns {Object} A plain object with the address information
  */
 Address.prototype.toObject = function toObject() {
   return {
@@ -439,7 +451,7 @@ Address.prototype.toObject = function toObject() {
 };
 
 /**
- * @returns {Object} An object of the address
+ * @returns {String} A JSON representation of a plain object with the address information
  */
 Address.prototype.toJSON = function toJSON() {
   return JSON.stringify(this.toObject());
diff --git a/test/address.js b/test/address.js
index 7b6696c..0e8a1fb 100644
--- a/test/address.js
+++ b/test/address.js
@@ -21,7 +21,7 @@ describe('Address', function() {
   var buf = Buffer.concat([new Buffer([0]), pubkeyhash]);
   var str = '16VZnHwRhwrExfeHFHGjwrgEMq8VcYPs9r';
 
-  it('should throw an error because of missing data', function() {
+  it('can\'t build without data', function() {
     (function() {
       return new Address();
     }).should.throw('First argument is required, please include address data.');
@@ -116,57 +116,57 @@ describe('Address', function() {
 
   describe('validation', function() {
 
-    it('should describe this livenet address as an invalid testnet address', function() {
+    it('getValidationError detects network mismatchs', function() {
       var error = Address.getValidationError('37BahqRsFrAd3qLiNNwLNV3AWMRD7itxTo', 'testnet');
       should.exist(error);
     });
 
-    it('should should return a true boolean', function(){
+    it('isValid returns true on a valid address', function(){
       var valid = Address.isValid('37BahqRsFrAd3qLiNNwLNV3AWMRD7itxTo', 'livenet');
       valid.should.equal(true);
     });
 
-    it('should should return a false boolean', function(){
+    it('isValid returns false on network mismatch', function(){
       var valid = Address.isValid('37BahqRsFrAd3qLiNNwLNV3AWMRD7itxTo', 'testnet');
       valid.should.equal(false);
     });
 
-    it('should validate addresses', function() {
+    it('validates correctly the P2PKH test vector', function() {
       for (var i = 0; i < PKHLivenet.length; i++) {
         var error = Address.getValidationError(PKHLivenet[i]);
         should.not.exist(error);
       }
     });
 
-    it('should validate p2sh addresses', function() {
+    it('validates correctly the P2SH test vector', function() {
       for (var i = 0; i < P2SHLivenet.length; i++) {
         var error = Address.getValidationError(P2SHLivenet[i]);
         should.not.exist(error);
       }
     });
 
-    it('should validate testnet p2sh addresses', function() {
+    it('validates correctly the P2SH testnet test vector', function() {
       for (var i = 0; i < P2SHTestnet.length; i++) {
         var error = Address.getValidationError(P2SHTestnet[i], 'testnet');
         should.not.exist(error);
       }
     });
 
-    it('should not validate addresses with params', function() {
+    it('rejects correctly the P2PKH livenet test vector with "testnet" parameter', function() {
       for (var i = 0; i < PKHLivenet.length; i++) {
         var error = Address.getValidationError(PKHLivenet[i], 'testnet');
         should.exist(error);
       }
     });
 
-    it('should validate addresses with params', function() {
+    it('validates correctly the P2PKH livenet test vector with "livenet" parameter', function() {
       for (var i = 0; i < PKHLivenet.length; i++) {
         var error = Address.getValidationError(PKHLivenet[i], 'livenet');
         should.not.exist(error);
       }
     });
 
-    it('should not validate because of an invalid checksum', function() {
+    it('should not validate if checksum is invalid', function() {
       for (var i = 0; i < badChecksums.length; i++) {
         var error = Address.getValidationError(badChecksums[i], 'livenet', 'pubkeyhash');
         should.exist(error);
@@ -174,16 +174,21 @@ describe('Address', function() {
       }
     });
 
-    it('should not validate because of mismatched network', function() {
-      for (var i = 0; i < PKHLivenet.length; i++) {
-        var error = Address.getValidationError(PKHLivenet[i], 'testnet', 'pubkeyhash');
+    it('should not validate on a network mismatch', function() {
+      var error, i;
+      for (i = 0; i < PKHLivenet.length; i++) {
+        error = Address.getValidationError(PKHLivenet[i], 'testnet', 'pubkeyhash');
+        should.exist(error);
+        error.message.should.equal('Address has mismatched network type.');
+      }
+      for (i = 0; i < PKHTestnet.length; i++) {
+        error = Address.getValidationError(PKHTestnet[i], 'livenet', 'pubkeyhash');
         should.exist(error);
         error.message.should.equal('Address has mismatched network type.');
       }
-
     });
 
-    it('should not validate because of a mismatched type', function() {
+    it('should not validate on a type mismatch', function() {
       for (var i = 0; i < PKHLivenet.length; i++) {
         var error = Address.getValidationError(PKHLivenet[i], 'livenet', 'scripthash');
         should.exist(error);
@@ -191,7 +196,7 @@ describe('Address', function() {
       }
     });
 
-    it('should not validate because of non-base58 characters', function() {
+    it('should not validate on non-base58 characters', function() {
       for (var i = 0; i < nonBase58.length; i++) {
         var error = Address.getValidationError(nonBase58[i], 'livenet', 'pubkeyhash');
         should.exist(error);
@@ -199,28 +204,13 @@ describe('Address', function() {
       }
     });
 
-    it('should not validate addresses', function() {
-      for (var i = 0; i < badChecksums.length; i++) {
-        var error = Address.getValidationError(badChecksums[i]);
-        should.exist(error);
-      }
-    });
-
-    it('should validate testnet addresses', function() {
+    it('testnet addresses are validated correctly', function() {
       for (var i = 0; i < PKHTestnet.length; i++) {
         var error = Address.getValidationError(PKHTestnet[i], 'testnet');
         should.not.exist(error);
       }
     });
 
-    it('should not validate testnet addresses because of mismatched network', function() {
-      for (var i = 0; i < PKHTestnet.length; i++) {
-        var error = Address.getValidationError(PKHTestnet[i], 'livenet', 'pubkeyhash');
-        should.exist(error);
-        error.message.should.equal('Address has mismatched network type.');
-      }
-    });
-
   });
 
   describe('encodings', function() {
@@ -228,7 +218,7 @@ describe('Address', function() {
     it('should make an address from a buffer', function() {
       Address.fromBuffer(buf).toString().should.equal(str);
       new Address(buf).toString().should.equal(str);
-      Address(buf).toString().should.equal(str);
+      new Address(buf).toString().should.equal(str);
     });
 
     it('should make an address from a string', function() {
@@ -316,13 +306,14 @@ describe('Address', function() {
     });
 
     it('should make this address from a compressed pubkey', function() {
-      var pubkey = PublicKey.fromDER(new Buffer('0285e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b004', 'hex'));
+      var pubkey = new PublicKey('0285e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b004');
       var address = Address.fromPublicKey(pubkey);
       address.toString().should.equal('19gH5uhqY6DKrtkU66PsZPUZdzTd11Y7ke');
     });
 
     it('should make this address from an uncompressed pubkey', function() {
-      var pubkey = PublicKey.fromDER(new Buffer('0485e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b004833fef26c8be4c4823754869ff4e46755b85d851077771c220e2610496a29d98', 'hex'));
+      var pubkey = new PublicKey('0485e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b00' +
+          '4833fef26c8be4c4823754869ff4e46755b85d851077771c220e2610496a29d98');
       var a = Address.fromPublicKey(pubkey, 'livenet');
       a.toString().should.equal('16JXnhxjJUhxfyx4y6H4sFcxrgt8kQ8ewX');
       var b = new Address(pubkey, 'livenet', 'pubkeyhash');
@@ -379,7 +370,7 @@ describe('Address', function() {
 
   describe('#toBuffer', function() {
 
-    it('should output this known hash', function() {
+    it('3c3fa3d4adcaf8f52d5b1843975e122548269937 corresponds to hash 16VZnHwRhwrExfeHFHGjwrgEMq8VcYPs9r', function() {
       var address = new Address(str);
       address.toBuffer().slice(1).toString('hex').should.equal(pubkeyhash.toString('hex'));
     });
@@ -388,37 +379,37 @@ describe('Address', function() {
 
   describe('#json', function() {
 
-    it('should output/input a JSON object', function() {
-      var address = Address.fromJSON(new Address(str).toJSON());
-      address.toString().should.equal(str);
-    });
-
-    it('should output/input a JSON string', function() {
+    it('roundtrip to-from-to', function() {
       var json = new Address(str).toJSON();
       var address = Address.fromJSON(json);
       address.toString().should.equal(str);
     });
 
+    it('checks that the string parameter is valid JSON', function() {
+      expect(function() {
+        return Address.fromJSON('¹');
+      }).to.throw();
+    });
   });
 
   describe('#toString', function() {
 
-    it('should output a livenet pubkeyhash address', function() {
+    it('livenet pubkeyhash address', function() {
       var address = new Address(str);
       address.toString().should.equal(str);
     });
 
-    it('should output a scripthash address', function() {
+    it('scripthash address', function() {
       var address = new Address(P2SHLivenet[0]);
       address.toString().should.equal(P2SHLivenet[0]);
     });
 
-    it('should output a testnet scripthash address', function() {
+    it('testnet scripthash address', function() {
       var address = new Address(P2SHTestnet[0]);
       address.toString().should.equal(P2SHTestnet[0]);
     });
 
-    it('should output a testnet pubkeyhash address', function() {
+    it('testnet pubkeyhash address', function() {
       var address = new Address(PKHTestnet[0]);
       address.toString().should.equal(PKHTestnet[0]);
     });