This book provides an introduction to the theory of relativity, both special and general, to be used in a one-term course for undergradu- ate students, mainly physics and math majors, early in their studies. It is important that students have a good understanding of relativity to appreciate the unifying principles and constraints it brings to both classical and quantum theories. The understanding of such a beauti- ful subject can bring a great deal of satisfaction and excitement to the student.
The history of both special and general relativity is given short shrift in the book, however. I believe that an initial study of relativity is best done by a straightforward, linear development of the theory, without the twists and turns that are inevitably a part of a theory’s history. With such an approach, students can understand and appre- ciate the structure of the resulting theory more quickly than if the historical path is followed. The historical path has an interest and value of its own, but the illumination of this path is best done by histo- rians of science. Therefore, for example, I have not discussed Mach’s principle—-the principle that inertial frames are determined by the distribution of mass in the universe. Undoubtedly, Einstein was influ- enced by Mach, but in the end the answer to the question “Does Einstein’s general relativity obey Mach’s principle?” is elusive.
The target audience imposes constraints on what material is included and on the level of sophistication, especially mathematical sophistication, employed. I assume the student has had an introduc- tory course in physics, a knowledge of basic calculus, including simple differential equations and partial derivatives, and linear algebra, including vectors and matrices. In addition, it is useful, though not necessary, that students be able to use a symbolic mathematical program such as Mathematica or Maple. Most physics majors at American universities have the required background at the begin- ning of their third year, many as much as a year earlier.