This republication of Albert Einstein's introduction to his theory of relativity, written for the layperson, includes commentary by Robert Geroch (physics, University of Chicago) on the modern understanding of relativity, plus an introduction by Robert Penrose (mathematics, emeritus, Oxford University), framing Einstein's work within the history of science, and an essay on the cultural legacy of relativity theory by David C. Cassidy (natural sciences, Hofstra University). Einstein's preface, 32 chapters, and three appendices were originally published in 1920. The original version of Roger Penrose's introduction was first published in 2004 by The Folio Society Ltd