This book is a fitting tribute to Irving I. Gottesman by his colleagues and former students. There is a brief overview of behavioral genetic designs that helps to make it accessible for those who are unfamiliar with these methodologies. This overview is followed by chapters on substantive findings regarding genetic and environmental influences on topics as wide-ranging as schizophrenia, substance abuse, social attitudes, the relationship of personality and temperament to psychopathology, and ways in which marital status interacts with genotype to influence behavioral and health outcomes.

Several chapters are of interest for how they demonstrate the importance of genetically informative designs for interpreting data as much as for their substantive findings. David DiLalla and Greg Carey, for example, write about personality and psychopathology, but, perhaps more importantly, they illustrate the advantages of a genetically informative design and one way in which examining phenotypic correlations alone can be misleading.

In a thought-provoking chapter, Eric Turkheimer discusses the fact that behavioral genetic studies consistently find little effect of shared familial environments. He suggests that other social scientists are still probably correct in asserting that the family in which we are raised does make a difference, but his simulations suggest that the effects of shared environment are obscured in human studies because random genotypes cancel out differential environmental effects. Arguments are put forth from both sides, showing us that the nature-nurture debate is not dead yet. Everyone agrees that both genes and environment are important in development and behavior, but beyond that most general pronouncement the different camps are still competing over which is really most important.

The chapter by Daniel Hanson presents a provocative theory of schizophrenia. Thinking outside the box, he suggests that schizophrenia may be analogous to a disease such as polio in which only 1%–2% of those exposed to the virus develop paralysis. Consequently, paralysis may not be the most useful phenotype to study. Moreover, there may not be genes for the illness per se but, rather, genes that confer resistance. This raises another important issue for psychiatric genetic research—the need to consider alternate phenotypes.

Although everyone now understands that both genes and environment are important, behavioral genetics is still a long way from being a central part of training in either psychiatry or psychology research. I continue to be struck by the fact that one of the most common questions I am asked about my own twin research is still, "Are they all identical?" To the behavioral genetics researcher, of course, this conveys a lack of basic understanding of the method. Yet with recent advances in molecular genetics and genomics, understanding behavioral genetics and conducting research that is genetically informative will surely become increasingly important. With these concerns in mind, this book serves as an excellent introduction for newcomers to behavioral genetics, while it also addresses sophisticated and provocative issues that will be both interesting and useful to more seasoned researchers.