This subject was chosen by Professor Cunningham for the third Huxley Memorial Lecture of the Anthropological Institute. He deals with it in a thorough manner and with wide knowledge of the extensive literature. He regards right-handedness as an organic acquirement of early man, due to natural selection. There is no good reason to show that monkeys are right-handed, and evidence obtained from Dr. Taylor, at the Darenth Asylum, showed that microcephalic idiots tend to be ambidextrous (five right-handed, four ambidextrous, one left-handed) The functional pre-eminence of the brain is the cause, and not the result, of right-handedness. Left-handedness may be regarded as due “probably to a transposition of the two cerebral hemispheres in the same way that transposition, either partial or complete, of the thoracic and abdominal viscera occurs.” It is noteworthy that there is a large proportion of left-handedness in those showing transposition of the viscera.