Two crucial human cognitive goals are to understand and to learn. Both goals often require active management, actively questing for knowledge. Children’s questions, both purposeful and incidental, both verbal and nonverbal, do this. Questions start early in life, change in nature and influence, but powerfully impact cognitive development all along the way. Often they do so as an antecedent and a consequence of children’s investment in explanatory understanding. I use my research and the research of my collaborators to address these topics as well as describe several of the steps and processes whereby questions and explanations drive the development of children’s comprehension and learning.