The chapters in this volume address the need for a better understanding of the development of intersecting identities over age and context. The chapters provide valuable insights into the development of identities, particularly group identities. They highlight common processes across identities, such as the role of contrast and comparison and the need for individual effort in identity formation. They suggest the value of studying multiple identities in interaction and using interdisciplinary approaches. However, research across identities and disciplines poses challenges for investigators. These challenges can be met and the field advanced by collaborative studies among scholars who represent different disciplines and have studied different identities.