Myrtle McGraw’s pioneering contributions to the field of child development have been readily acknowledged and documented, yet controversy persists among psychologists as to how to interpret her ideas about significant factors that influence learning. This collection includes some of McGraw’s most cogent work, including five previously unpublished essays that address misconceptions and clarify her principles of development. These essays demonstrate that McGraw conceived of development as a continuous interaction between neural and behavioral growth processes that could not be reduced to either heredity or environment.The editors document McGraw’s little-known collaboration in the 1930s with John Dewey and several other notable scientists. Dewey believed their research promised to “revolutionize work in the field of child study.” Their collaboration brings to light new evidence that McGraw’s work made use of novel methods to study developmental behavior and enabled Dewey to examine the origin and role of judgment in inquiry. Five other contributors discuss specific issues and episodes that illuminate why McGraw’s scientific innovations remain pertinent to researchers in infant motor development.