discussed online at The Genesis of General Relativity. Brans, Carl H.; "The roots of scalar-tensor theory: an approximate history", . Discusses the history of attempts to construct gravity theories with a scalar field and the relation to the equivalence principle and Mach's principle. Misner, Charles W.; Thorne, Kip S.; and Wheeler, John A.; Gravitation, New York: W. H. Freeman and Company, 1973, Chapter 16 discusses the equivalence principle. Ohanian, Hans; and Ruffini, Remo; Gravitation and Spacetime 2nd edition, New York: Norton, 1994, Chapter 1 discusses the equivalence principle, but incorrectly, according to modern usage, states that the strong equivalence principle is wrong. Uzan, Jean-Philippe; "The fundamental constants and their variation: Observational status and theoretical motivations", Reviews of Modern Physics 75, 403 (2003). This technical article reviews the best constraints on the variation of the fundamental constants. Will, Clifford M.; Theory and experiment in gravitational physics, Cambridge, UK: Cambridge University Press, 1993. This is the standard technical reference for tests of general relativity. Will, Clifford M.; Was Einstein Right?: Putting General Relativity to the Test, Basic Books (1993). This is a popular account of tests of general relativity. Will, Clifford M.; The Confrontation between General Relativity and Experiment, Living Reviews in Relativity (2006). An online, technical review, covering much of the material in Theory and experiment in gravitational physics. The Einstein and strong variants of the equivalence principles are discussed in sections 2.1 and 3.1, respectively. Friedman, Michael; Foundations of Space-Time Theories, Princeton, New Jersey: Princeton University Press, 1983. Chapter V discusses the equivalence principle. External links Equivalence Principle at NASA, including tests Introducing The Einstein Principle of Equivalence from Syracuse University The Equivalence Principle at MathPages The Einstein Equivalence Principle at Living Reviews on General Relativity General relativity Fictitious forces Albert Einstein Principles Acceleration Philosophy of astronomy Articles containing video clips