The intersecting of masculinity studies and childhood studies since the 1990s has been expansive. Questions of gender have increasingly invoked questions of development, and demarcating boyhood has become a problem central to gender studies, indexical to more encompassing riddles of temporal masculinities and masculine temporalities. Motivation for theory and research on boyhood masculinities shifted considerably during the 20th century, from psychoanalysis and the popular reformatory “boyology” scene (first half of the 20th century) to the social and medical psychology of sex roles and gender dysphoria (1960s and 1970s) and gender identity disorder (1980s) to the current (1990s–2010s) culture wars over Schooling, Medicalization, sexual abuse and harassment, and heteronormativity. In the early 21st century, attention to boyhood masculinities derives its largest impetus from a heterogeneous spectrum of increasingly mainstreamed controversies, prominently including gender gaps and gender-specific drops in enrollment, literacy, performance, and retention, and purportedly related feminization or demasculinization of education (see Schooling: “Boy Problem,” “Boy Turn,” and Feminization). All of these controversies show a heavy Anglo-American slanting, with most publications emerging from the United States, the United Kingdom, Australia, and Canada. Sections in this article provide an orientation to general academic venues (Encyclopedias, Journals, Synoptic Works) for introductory reading. Development of Gender Identity/Difference, Cross-Cultural and Non-Western Studies, Boys’ Geographies, and Ethnographies illustrate the broad angle of boyhood studies, while Historical Studies covers major Anglo-American (United States, Britain and Ireland, Canada, Australia) and emergent (Africa, Asia) contexts for scholarship. Other sections follow thematic interests more or less familiar to childhood studies researchers (Schooling, Sexualities, Representations and Mediations, Medicalization, Toys, Material Culture, and Technology). A separate section Boys’ Literature offers general, American historical, and British historical resources.