A keyboard that is attached on to the back of a mobile computing device, having keys that are facing rearward away from the user as the user holds and faces the display screen of the mobile computing device. When the user holds the mobile computing device with both hands at the bottom or side edges, his/her fingers are free to press the rearward-facing keys of the attached keyboard. The keys are divided into one partial field for the left-hand fingers and another partial field for the right-hand fingers. The keys within their respective partial fields are placed in mirror-opposite of the positions that would have been in a front-facing keyboard that is laid before the user. This rearward-facing key orientation allows the user to use the same rapid typing system, such as that of the QWERTY keyboard layout, on the rearward-facing keyboard as he/she would on a traditional front-facing keyboard.