What constitutes the content for teaching and learning in the 21st century? How should content be selected and organized into school subjects in the curriculum? How are school subjects related to academic disciplines? These questions, concerning what is taught and learned in school, are vital for curriculum policy-making, curriculum planning and development, and classroom curriculum enactment in today’s context. To address the above questions, I first look at various conceptions of the aim of schooling and then examine three possible relationships between school subjects and academic disciplines. Afterward, I discuss the formation of a school subject from the perspective of curriculum making and then proceed to analyze three specific cases of constructing a school subject, with a focus on issues of content selection and organization for teaching and learning. I conclude by raising a set of questions concerning content selection and organization with a central concern for the development of human powers or capabilities (capacities or abilities, ways of thinking, understanding worlds) in the 21st century.