Originally proposed in 1975, the transactional model has become central to our understanding of how nature and nurture interact in the development of positive and negative outcomes for children. Although scientists have long acknowledged that nature and nurture work together in producing particular developmental outcomes, such cooperation has been difficult to demonstrate because of inadequate conceptual models, experimental designs or statistical methodologies. This book documents the state-of-the-art research in developmental psychology for overcoming these inadequacies, and present new ideas for future work.