Optimized keyboard for handheld thumb-typing and touch-typing

A handheld device configured for thumb typing and touch typing, comprising:

• a body having a front face and a rear face;
• a keyboard at the front face of the body comprising a plurality of keys having alphabetic characters associated therewith, said alphabetic characters arranged in one of a QWERTY layout, an AZERTY layout, a QWERTZ layout, QZERTY layout, and a Dvorak layout;
• a portion of said plurality of keys also having numerals associated therewith, said numerals arranged in a telephone keypad layout according to ITU Standard E.161;
• said keyboard has a width greater than about 100 millimeters and less than about 160 millimeters, and each of said plurality of keys has a width that is approximately 10 millimeters to 16 millimeters;
• said plurality of keys having alphabetic characters being arranged such that a first subset of keys of the plurality of keys on the left side of a vertical centerline of the keyboard can be actuated with a left thumb when the device is held by a user without repositioning cradling hands of the user and a second subset of keys of the plurality of keys on the right side of the vertical centerline of the keyboard can be actuated with a right thumb when the device is held by a user without repositioning the cradling hands of the user;
• and
• said plurality of keys also being positioned such that when the hands of the user are placed on top of the plurality of keys, said keys having alphabetic characters can be actuated by the digits of the user without substantially repositioning of hands of the user from a resting position on top of the plurality of keys.