diff --git a/cores/arduino/HID.cpp b/cores/arduino/HID.cpp
index b508f10..378a157 100644
--- a/cores/arduino/HID.cpp
+++ b/cores/arduino/HID.cpp
@@ -401,18 +401,32 @@ const uint8_t _asciimap[128] =
 
 uint8_t USBPutChar(uint8_t c);
 
+// press() adds the specified key (printing, non-printing, or modifier)
+// to the persistent key report and sends the report.  Because of the way 
+// USB HID works, the host acts like the key remains pressed until we 
+// call release(), releaseAll(), or otherwise clear the report and resend.
 size_t Keyboard_::press(uint8_t k) 
 {
 	uint8_t i;
-	k = pgm_read_byte(_asciimap + k);
-	if (!k) {
-		setWriteError();
-		return 0;
-	}
-	if (k & 0x80) {
-		_keyReport.modifiers |= KEY_MODIFIER_LEFT_SHIFT;
-		k &= 0x7F;
+	if (k >= 136) {			// it's a non-printing key (not a modifier)
+		k = k - 136;
+	} else if (k >= 128) {	// it's a modifier key
+		_keyReport.modifiers |= (1<<(k-128));
+		k = 0;
+	} else {				// it's a printing key
+		k = pgm_read_byte(_asciimap + k);
+		if (!k) {
+			setWriteError();
+			return 0;
+		}
+		if (k & 0x80) {
+			_keyReport.modifiers |= 0x02;	// the left shift modifier
+			k &= 0x7F;
+		}
 	}
+	
+	// Add k to the key report only if it's not already present
+	// and if there is an empty slot.
 	if (_keyReport.keys[0] != k && _keyReport.keys[1] != k && 
 		_keyReport.keys[2] != k && _keyReport.keys[3] != k &&
 		_keyReport.keys[4] != k && _keyReport.keys[5] != k) {
@@ -432,17 +446,40 @@ size_t Keyboard_::press(uint8_t k)
 	return 1;
 }
 
+// release() takes the specified key out of the persistent key report and
+// sends the report.  This tells the OS the key is no longer pressed and that
+// it shouldn't be repeated any more.
 size_t Keyboard_::release(uint8_t k) 
 {
+	/*
 	uint8_t i;
 	k = pgm_read_byte(_asciimap + k);
 	if (!k) {
 		return 0;
 	}
 	if (k & 0x80) {
-		_keyReport.modifiers |= KEY_MODIFIER_LEFT_SHIFT;
+		_keyReport.modifiers |= 0x02;	// the left shift modifier
 		k &= 0x7F;
 	}
+	*/
+	uint8_t i;
+	if (k >= 136) {			// it's a non-printing key (not a modifier)
+		k = k - 136;
+	} else if (k >= 128) {	// it's a modifier key
+		_keyReport.modifiers &= ~(1<<(k-128));
+		k = 0;
+	} else {				// it's a printing key
+		k = pgm_read_byte(_asciimap + k);
+		if (!k) {
+			return 0;
+		}
+		if (k & 0x80) {
+			_keyReport.modifiers &= ~(0x02);	// the left shift modifier
+			k &= 0x7F;
+		}
+	}
+	
+	// Test the key report to see if k is present.  Clear it if it exists.
 	for (i=0; i<6; i++) {
 		if (_keyReport.keys[i] == k) {
 			_keyReport.keys[i] = 0x00;
@@ -468,6 +505,7 @@ void Keyboard_::releaseAll(void)
 	sendReport(&_keyReport);
 }
 
+// type() does a press and release of the specified key. 
 size_t Keyboard_::type(uint8_t c)
 {
 	releaseAll();
diff --git a/cores/arduino/USBAPI.h b/cores/arduino/USBAPI.h
index 3f71856..05f7318 100644
--- a/cores/arduino/USBAPI.h
+++ b/cores/arduino/USBAPI.h
@@ -70,14 +70,42 @@ extern Mouse_ Mouse;
 //================================================================================
 //	Keyboard
 
-#define KEY_MODIFIER_LEFT_CTRL		0x01
-#define KEY_MODIFIER_LEFT_SHIFT		0x02
-#define KEY_MODIFIER_LEFT_ALT		0x04
-#define KEY_MODIFIER_LEFT_GUI		0x08
-#define KEY_MODIFIER_RIGHT_CTRL		0x010
-#define KEY_MODIFIER_RIGHT_SHIFT	0x020
-#define KEY_MODIFIER_RIGHT_ALT		0x040
-#define KEY_MODIFIER_RIGHT_GUI		0x080
+#define KEY_LEFT_CTRL		0x80
+#define KEY_LEFT_SHIFT		0x81
+#define KEY_LEFT_ALT		0x82
+#define KEY_LEFT_GUI		0x83
+#define KEY_RIGHT_CTRL		0x84
+#define KEY_RIGHT_SHIFT		0x85
+#define KEY_RIGHT_ALT		0x86
+#define KEY_RIGHT_GUI		0x87
+
+#define KEY_UP_ARROW		0xDA
+#define KEY_DOWN_ARROW		0xD9
+#define KEY_LEFT_ARROW		0xD8
+#define KEY_RIGHT_ARROW		0xD7
+#define KEY_BACKSPACE		0xB2
+#define KEY_TAB				0xB3
+#define KEY_RETURN			0xB0
+#define KEY_ESC				0xB1
+#define KEY_INSERT			0xD1
+#define KEY_DELETE			0xD4
+#define KEY_PAGE_UP			0xD3
+#define KEY_PAGE_DOWN		0xD6
+#define KEY_HOME			0xD2
+#define KEY_END				0xD5
+#define KEY_CAPS_LOCK		0xC1
+#define KEY_F1				0xC2
+#define KEY_F2				0xC3
+#define KEY_F3				0xC4
+#define KEY_F4				0xC5
+#define KEY_F5				0xC6
+#define KEY_F6				0xC7
+#define KEY_F7				0xC8
+#define KEY_F8				0xC9
+#define KEY_F9				0xCA
+#define KEY_F10				0xCB
+#define KEY_F11				0xCC
+#define KEY_F12				0xCD
 
 //	Low level key report: up to 6 keys and shift, ctrl etc at once
 typedef struct