Connects Daryl Siedentop's speech, "Content Knowledge for Physical Education," with two others: "Curriculum Innovation: Toward the 21st Century" and "Physical Activity Cultures for Children and Youth: Redefining Physical Education," responding to seven issues: the nature of content knowledge; status, professional knowledge, and practical knowledge; purposes of physical education; disciplines and school subjects; contemporary context of knowledge; novelty, "new times," and identity; and moving forward. (SM)