Eleven papers that forged the general and special theories of relativity include seven papers by Einstein, two by Lorentz, and one each by Minkowski and Weyl. This collection of original papers on the special and general theories of relativity is an unabridged translation of the 4th edition of Das Relativitatsprinzip, together with a revised edition of an additional paper by H. A. Lorentz. CONTENTS: I. "Michelson's Interference Experiment" by H. A . Lorentz. II. "Electromagnetic Phenomena in a System Moving with any Velocity Less than that of Light" by H. A . Lorentz. Ill. "On the Electrodynamics of Moving Bodies" by A. Einstein. IV. "Does the Inertia of a Body Depend Upon its Energy-Content?" by A. Einstein. V. "Space and Time" by H. Minkowski. VI. "On the Influence of Gravitation on the Propagation of Light" by A. Einstein. VII. "The Foundation of the General Theory of Relativity" by A. Einstein. VIII. "Hamilton's Principle and the General Theory of Relativity" by A. Einstein. IX. "Cosmological Considerations on the General Theory of Relativity" by A. Einstein. X. "Do Gravitational Fields Play an Essential Part in the Structure of the Elementary Particles of Matter?" by A. Einstein. XI. "Gravitation and Electricity" by H. Weyl. AUTHOR: In addition to conducting the research that culminated in his acclaimed theories of relativity, Albert Einstein (1879-1955) taught and lectured at universities around the world. Einstein received numerous awards and honorary doctorate degrees in science, medicine, and philosophy, and he remains a towering symbol of intellectual and imaginative achievement.