As Infant and Child Development enters its 3rd decade, we were delighted to guest edit this Special Issue on Family Processes and Child Adjustment. Our aim was to bring together recent research that considers the mechanisms whereby families influence children's behavioural and emotional adjustment. This issue brings together cutting-edge research concerning family processes that includes sophisticated methodologies and techniques designed for longitudinal family data.

Reflecting the sub-title of the journal, “An International Journal of Research,” the studies include samples from Israel (Gueron-Sela, Regev, & Atzaba-Poria) and the U.K. (Ensor, Roman, Hart, & Hughes) as well as North America. In addition, Gueron-Sela and colleagues consider ethnic majority and minority families, and Boeldt and colleagues use a sample of identical and fraternal twins to explore genetic and environmental mechanisms. Furthermore, large representative samples are included (Hardaway, Wilson, Shaw, & Dishion; MacKenzie, Nicklas, Waldfogel, & Brooks-Gunn) which address the frequent criticism of earlier work focused on small middle-class samples. As well as increasing generalizability, larger samples afford the power to undertake more complex analysis of small, but systematic effects.

Analytically, several techniques are noteworthy. Path analysis and latent growth curve modeling are used by Ensor and colleagues to test the longitudinal stability of measurement structures as well as to chart children's developmental trajectories. The multilevel modeling used by Meunier et al. enables consideration of all children within families. This method does far more than “fix” the problem of non-independence of sibling data; multilevel modeling allows individual differences within families to be assessed alongside differences between families. In this way the process of socalization can be located as differentiating siblings, and/or differentiating family units from one another. Going one step further, Boeldt et al. demonstrate how behavioural genetic modeling can reveal the extent to which individual differences may be explained by genetic and environmental influences.

A perspective that permeates many of the contributions is that of Bronfenbrenner's ecological systems theory, in which the multiple layers of proximal to distal contextual factors are considered as mediators and moderators of family processes. At the least, ecological factors are statistically “controlled” when reporting the effects of parenting (MacKenzie et al.). Gueron-Sela et al. go beyond simplistic social address models by elucidating a process involving corporal punishment whereby ethnic minority children's prosocial behaviour lagged behind that of their majority-group peers. Hardaway et al. examine household chaos among other predictors of child self-regulation and behavioral problems over early childhood. Meunier et al. extend from chaos to examine a host of contextual factors spanning educational level, parenting, depression, history of abuse, teen motherhood, household composition, marital conflict, neighbourhood quality, collective efficacy, and perslonal safety/victimization. They find that these ecological conditions exacerbate the deleterious consequences of negative parenting.

This outstanding collection of papers examining family processes and child adjustment represent the leading edge of this dynamic field of research. The issue sets the stage for new and important discoveries that not only will advance our understanding of children's development in distinct contexts, but also will lead to innovations in prevention and intervention efforts to improve the lives of children and their families.