The author and his collaborators have studied skeletal maturation by means of serial roentgenograms of a large number of selected males and females at frequent intervals throughout the growth period. Standard observations have been set up at three or six months intervals from three months after birth to 16 years in girls and 19 years in boys, at which dates maturity is reached. Forty standard roentgenograms of the hand of the male and thirty-five of the female covering the period of maturation are reproduced and the changes recorded with great precision. Maturation is observed to proceed more rapidly in the female throughout the entire period but more noticeably after the first year. This is a masterly study of skeletal growth and it is to be hoped that the author will publish similar studies which he indicates he has made of the rest of the skeleton.