Book excerpt: If you had just one wish for the study of human development, what would it be? How would it advance the field? And what would it take for your vision to be realized? This was the charge given to twenty-eight scholars, coming from different disciplines and fields, and who study different periods of the life course. This book compiles provocative contributions from a wide range of established scholars, organized into seven thematic areas: conceptual advances; systems, levels, and contexts; individual differences; methodological advances; harnessing science for human welfare and social justice; underexplored life course dynamics; and interdisciplinary collaboration and playing well with others. This book was originally published as a special issue of Research in Human Development.