Dr. August Dvorak
, in addition to his highly efficient two-handed keyboard layout, created two single-handed layouts as well. Colonel Robert Allen had lost an arm in World War II
and asked Dr Dvorak to design a keyboard for him so that he could resume his writing. Dvorak created a left-handed and a right-handed keyboard layout. After about 10 weeks of practice, Colonel Allen was able to achieve a speed of about 56 wpm.