Recent research on the neuroscience and genetics of attention-deficit hyperactivity disorder (ADHD) has transformed the intellectual landscape of its discourse, if not of modern child neuropsychiatry. This slender volume, with many high-quality reviews, represents one of its landmarks. It provides a state-of-the-art summary of major findings in both behavioural (quantitative) and molecular genetics of this fascinating disorder. Yet the editors go beyond the remits of such an undertaking: it proposes many fresh questions, as well as providing a critique of the limitations and methodological issues of works hitherto undertaken. This is therefore a book that would interest and intrigue non-specialists and experts alike.

The bulk of the book is on quantitative genetics, that is, genetic epidemiology based on twin and adoption studies. There are also chapters on molecular genetics, which deal with DNA, alleleic frequency and candidate genes. These are two distinct intellectual disciplines that are sharply demarcated by differing methodologies and techniques. The editors have included an introductory chapter on quantitative genetics (Chapter 2) to equip non-specialist readers with basic principles of the subject and explanations on path diagrams. Thus, non-specialists need not be deterred. Chapter 3 examines the diagnostic validity of ADHD and its subtypes in relation to latent genetic substrates from a quantitative genetic perspective. This is an excellent piece, including the original analysis on large-scale Australian Twin ADHD Project data. Chapter 4 investigates ADHD from a longitudinal developmental perspective. Three subsequent chapters focus on the quantitative genetics of three common groups of comorbid conditions in relation to ADHD: speech and language disorders; specific reading/spelling disability; and oppositional defiant conduct disorder. Their complex but fascinating relationships with ADHD are examined and decomposed at both the phenotypical and genetic levels. These are accessible and well-referenced reviews, written by leading experts in these fields. Chapter 8 investigates the gender-modifying effect on the prevalence and severity of ADHD, and it includes fresh evidence that supports the polygenic multiple-threshold model. This is a thought-provoking piece that is both original and informative. Chapter 9 summarises the findings on single-gene studies of ADHD. Chapter 10 critically reviews the methodological issues and strategies of molecular genetics, with a short summary of well-known candidate genes. The chapter on comorbid Tourette syndrome gives an informative description of the condition, its neuropsychological correlates and patterns of familial inheritance. The concluding chapter provides a most authoritative critique of the reported findings, their methodological limitations and future directions of research.

This book gives an excellent, comprehensive review of major findings on the genetics of ADHD. It also examines the genetics of other comorbid conditions in relation to ADHD, in addition to exploring a broader view of ADHD in terms of both diagnostic validity and developmental variants. There are many fresh polemics, insights and original ideas, which will widen the reader's intellectual horizons to reach beyond the enclosed realms of ‘heritability’ and ‘candidate genes’.