In the past several decades, research on emotional development has flourished. Scientists have made progress in understanding infants', children's, and adults' abilities to recognize, communicate, and regulate their emotions. However, many questions remain unanswered or only partly answered. We are poised to move from descriptions of aspects of emotional functioning to conceptualizing and studying the developmental mechanisms that underlie those aspects. The gaps in our knowledge provide numerous opportunities for further investigation. With this special issue of Developmental Psychology, we aim to stimulate such progress, especially among colleagues at the beginning of their careers. The articles in this issue are intended to challenge our concepts and take research on emotional development in new directions. Toward this end, this special issue includes empirical studies, theoretical articles, novel conceptualizations, methodological innovations, and invited commentaries from scholars across a range of disciplines. In this introductory essay, we briefly review the history of research on emotional development and provide an overview of the contributions of this special issue with thoughts about the current state of the developmental science and areas in which further advancement on emotional development must be made. These include understanding the nature of emotion itself, identifying the mechanisms that produce developmental changes, examining emotion regulation within differing social contexts, and creating measures of culture that acknowledge globalization, historical change, and within-culture differences. (PsycINFO Database Record (c) 2019 APA, all rights reserved).