While genetic linkages to a variety of disorders have been suspected for decades, it has only been relatively recently that these linkages have come to be understood to a greater degree. The search for the genetic basis of some neurodevelopmental disorders, such as learning disabilities, has been elusive and fraught with complex hurdles, the genetic basis of other neurodevelopmental disorders, such as Down syndrome, has been much more clear. Other childhood disorders, such as Turner syndrome and fragile X syndrome, also documented clearly defined genotypes. Even when a clear genetic contribution is known (i.e., the genotype), the exact neurobehavioral manifestations (i.e., the phenotypes) remain unclear or poorly documented for many disorders. This edited volume addresses this quest and, perhaps, provides one of the most comprehensive descriptions of the available literature in the interface between genetics and behavior in childhood. As noted by the editors, one of the major objectives of this text is to provide students, clinicians, and researchers with a working knowledge base of behavioral genetics. In this regard, the editors wanted to provide a comprehensive text that was “organized in a framework that is understandable and immediately useful in clinical practice” (p. 6).