Einstein's comprehensive 1907 essay on relativity, part I, H.M. Schwartz, Am. J. Phys. 45(6), June 1977
As an important sequel to his first paper on relativity, Einstein's extensive discussion of the subject in the 1907 issue of Jahrbuch der Radioaktivität und Elektronik, including a first exposition of his embryonic ideas on gravitation, is of intrinsic as well as considerable historical interest. In this, the first of three parts dealing with Einstein's essay, a translation is presented of presented of the Introduction and of Part I, which is concerned with relativistic kinematics.