This handbook is dedicated to a phase of life (0 - 3 years) in which there is still much to discover. The aim is not only to present recent developments and trends in toddler research but also to take stock against the backdrop of the existing diversity of knowledge: Where does toddler research stand after about 30 years of intensive research efforts? What are the topics? What theoretical orientations guide the research? What methods are being used? In which fields of study are findings being applied, after longitudinal studies have replaced cross-sectional approaches and both ecological and systemic perspectives have gained broad acceptance? A special feature of this book is the detailed presentation of developmental psychological methods.