The historical forces that have contributed to our current views of neurobehavioral development (and thus to the fields of developmental psychobiology and neuroethology) are many and varied. Although similar statements might be made about almost any field of science, it is in particular true of this field, which represents a kind of mongrel discipline derived from at least three major sources (psychology, embryology, and neuroscience) and several more minor ones (including developmental psychology and psychiatry, psychoanalysis, education, zoology, ethology, and sociology). Although I attempt to demonstrate here how each of these sources may have influenced the emergence of a unified field of developmental psychobiology or developmental neuroethology, because the present article represents the first attempt of which I am aware to trace the history of these fields I am certain that there is considerable room for improvement, correction, and revision of the views expressed here. Accordingly, I consider this inaugural effort a kind of reconnaissance intended to trace a necessarily imperfect historic path for others to follow and improve upon. In the final analysis, I will be satisfied if this article only serves to underscore two related points: first is the value derived from historical studies of contemporary issues in development, and the second concerns the extent to which our current ideas and concepts about neurobehavioral development, ideas often considered new and contemporary, were already well known to those who came before us. The first point underscores the arguments expressed in the Introduction that the present must always be reconciled with the past, for the past is never entirely past. The second point returns full circle to an important thought expressed in the opening quotation to this article, namely, that even though our historic predecessors lacked much of the empirical facts available to us they were nonetheless able to attain a surprisingly deep understanding of neurobehavioral ontogeny.