First formulated in the early years of the 20th century, Einstein's theories of relativity overturned long-held concepts of space and time. They provided a radically new way of looking at the physical world and explanations for many questions unanswered by classical physics. Unfortunately, many laypeople consider relativity so abstruse and complicated that they despair of ever understanding it. In reality, the ideas, although profound, are quite simple. That simplicity is strikingly illuminated in this delightfully nontechnical book, which explains relativity in a straightforward, carefully illustrated manner the intelligent layperson can understand. A little high-school geometry will enable the reader to follow the discussion. Moreover, the book includes more than 60 drawings to illustrate concepts more clearly than verbal explanations could ever do. Beginning with the questions "What is Time?" and "What is Space?" the author gradually introduces concepts from ordinary geometry needed to follow the development of Einstein's ideas. Having grasped this foundation, the reader is prepared to understand the specific nature and ramifications of relativity theory. To further increase comprehension, the book is planned so that the text and illustrations face each other on a two-page spread, making it easy for the reader to refer from the text to the illustrations. Clear, engrossing and well-balanced, this remarkably accessible treatment offers an ideal introduction to one of the most important physical theories of the 20th century. It can be read with profit by high-school and college students, teachers, scientists, or any reader fascinated by Einstein's epoch-making theories and their far-reaching implications.