A series of six papers on “Youth Development in Europe: Transitions and Identities” has now been published in the European Psychologist throughout 2008 and 2009. The papers aim to make a conceptual contribution to the increasingly important area of productive youth development by focusing on variations and changes in the transition to adulthood and emerging identities. The papers address different aspects of an integrative framework for the study of reciprocal multiple person-environment interactions shaping the pathways to adulthood in the contexts of the family, the school, and social relationships with peers and significant others. Interactions between these key players are shaped by their embeddedness in varied neighborhoods and communities, institutional regulations, and social policies, which in turn are influenced by the wider sociohistorical and cultural context. Young people are active agents, and their development is shaped through reciprocal interactions with these contexts; thus, the developing individual both influences and is influenced by those contexts. Relationship quality and engagement in interactions appears to be a fruitful avenue for a better understanding of how young people adjust to and tackle development to productive adulthood.