The author surveys the hand's anatomy and functions, then traces left-handedness through archaeological, linguistic, and physiological evidence, arguing that preference for one hand has deep prehistoric roots and varied cultural responses. He examines how education, social stigma, and language have shaped attitudes toward left-handed people, analyzes dexterity shown in Paleolithic artifacts and handwriting forms, and discusses competing theories about neural control and psycho-physical mechanisms. Historical and comparative data are used to challenge efforts to suppress natural handedness and to recommend systematic training of skill in both hands as beneficial to individuals and society.