Background The Project Physics Course is based on the ideas and research of a national curriculum development project that worked in three phases. First, the authors — a high school physics teacher, a university physicist, and a professor of science education — collaborated to lay out the main goals and topics of a new introductory physics course. They worked together from 1962 to 1964 with financial support from the Carnegie Corporation of New York, and the first version of the text was tried out in two schools with encouraging results. This Text-Handbook is one of the many instructional materials developed for the Project Physics Course, including texts, laboratory experiments, films, and teacher guides. Development of the course has profited from the help of many colleagues listed at the front of the text units.