With this 2006 Annual Research Review, we have broken with the tradition that one associate editor is solely responsible for selecting the topics of papers to be commissioned. This time, the editors have jointly chosen the subjects and invited the authors. It may be indicative of the quality of the Journal that all authors who were invited to write these reviews readily agreed; and, as can be seen, there are many familiar names among the authors. Another consequence of the enthusiasm of authors to contribute to this year's Annual Research Review was that this issue is particularly large. I am very grateful to this outstanding group of contributors who, despite their busy lives, were willing to work with us under great time pressure. The very short time period between requesting these reviews and the present publication makes this issue especially timely. I also wish to express my gratitude to the referees whose comments further improved the papers.

In the first paper in this issue, Rutter, Moffitt and Caspi provide a very succinct and highly readable review of the diverse concepts that constitute gene-environment interplay. For the reader who is not very familiar with the technical details of how genes work, this review gives a captivating account of the role of genetic and environmental influences in the causation of psychopathology. Especially the illustrations of how environmental influences can turn genes on and off are intriguing. Although this kind of knowledge is not directly applicable to clinical practice, it gives the clinician a feeling of how the environment matters and in what ways environmental inputs can change the biology of the organism and produce long lasting effects.

The come back of the concept of psychopathy and an increase in use of this diagnosis in the literature makes it imperative to have a better understanding of the development of this disorder at multiple levels. Blair, Peschardt, Budhani, Mitchell and Pine provide a review of the role of genetic and social influences on the development of psychopathy in children and of neurobiological mechanisms mediating these influences. The authors argue that genetic causal influences are stronger than social ones for this disorder.

Currently there are a number of prospective, long-term longitudinal studies shedding light on the continuities and discontinuities in psychopathology from childhood into adulthood. Rutter, Kim-Cohen and Maughan review current knowledge of mechanisms involved in continuities and discontinuities in psychopathology and highlight directions and challenges for the future.

Adolescence is an intriguing developmental period with dramatic physical, cognitive and social changes. A growing body of empirical research on cognitive and neural development during puberty and adolescence is emerging. Blakemore and Choudhury provide a very clear review of brain development in adolescence and its implications for cognitive functioning in adolescence. The authors also discuss the implications for education and social policy.

In their review of epidemiological studies on common emotional and behavioral disorders in preschool children, Egger and Angold convincingly show that the rates of the common child psychiatric disorders and the patterns of comorbidity in preschoolers are similar to those seen in later childhood. The authors discuss the implications of these findings for research as well as for treatment, early intervention and prevention of problems in young children.

Michael Berger provides a challenging and inspiring model of early social development and of social dysfunctions in autism. The author highlights future directions for better understanding the very early social development, especially the young child's preparedness for social engagement.

Although completed suicide in young people fortunately is rare, suicidal ideation and suicide attempt are not. Bridge, Goldstein and Brent have undertaken a very thorough review of epidemiological data for youth suicide and suicidal behaviour. They also summarise current knowledge on risk and protective factors for youth suicide and suicidal behaviour. The authors provide a developmental-transactional model of youth suicidal behaviour and give recommendations relevant to clinical and public health issues.

The last paper is by Joel Nigg, who gives a very thoughtful review of conceptual issues in relating temperament to psychopathology and to personality in children. The author discusses a framework that can be used to highlight several specific temperamental pathways to specific types of psychopathology, including ADHD, conduct disorder and anxiety and depression. The author also provides challenges for future research.

This approach of editing the Annual Research Review by myself and the joint editors will be once-only, and it is my pleasure to announce that future issues of the Annual Research Review will be edited by Jim Leckman.

I am convinced that this issue of the Annual Research Review will be a pleasure to read and a very rich source of reference.