The First Two Years was first published in 1931.

A study of the locomotor development of twenty-five babies and its relationship to anatomical and physical development, individual differences, etc. Interesting theoretical implications for genetic and educational psychology. An admirable piece of scientific observation and much suggestive material on method for others interested in this field.

This is distinctly an intensive research. It is a report of an analysis of 16 babies [volume 1] from birth to two years of age. Though the study is promarily concerned with locomotor development, records of each baby were kept throughout the entire period on (1) anthropometric measurements, (2) health, nutrition, and general well-being, (3) motor coordination, (4) sensory development, (5) speech development, (6) interests, and (7) behavior and personality traits. [...] Child psychology needs more of such analytical studies.