Sexual Differentiation of the Brain will appeal primarily to researchers with specific interest in neuroendocrinological contributions to the sexual dimorphism of brain structures and neuropathways, predominantly in nonhumans. Collectively, the 16 chapters provide comprehensive review of our current understanding of the effects of hormonal steroids and their metabolites on brain development and the manner in which this correlates with specific behavioral functions. The clinician interested in furthering an understanding of sexually differentiated cognitive functioning or behavioral patterns in humans, may perceive discussion in many chapters as esoteric at best, or less charitably, as irrelevant. It is assumed that the reader has a prerequisite understanding of basic genetic and hormonal influences on brain development and subsequent behavioral manifestation. Although these issues are clarified by reference or associated discussion in several chapters, an introductory overview by the editor would have been beneficial. Similarly, the editor would have facilitated the reader's effort by organizing chapters according to findings of brain sexual dimorphism in humans versus “primitive” species, by clarifying the relevance of examining other species and/or by focusing attention to parallels in anatomical findings or in associated behavior.