This book is the outcome of a symposium where leading researchers, mainly in developmental psychology, came together to discuss the implications of the emerging developmental science and the holistic approach. In doing this, the authors wanted to honor a distinguished colleague, David Magnusson, and his career-long contributions to this field. The purpose of the book is to discuss the profound implications for developmental science of the holistic paradigm, especially with regard to the individual development within psychology. Against the background of their own empirical, theoretical, or methodological research, the authors have tried to identify what is needed for the developmental theory and methods within this paradigm and discuss possibilities and limitations in relation to conventional approaches.