This is half a book on quantum field theory. Non-Abelian gauge theory including the electro-weak theory and more recent developments are not covered. On the other hand, the topics which are included are treated in a completely modern manner. For example, the functional integral representation is used as the basis for the theory, and it is presented in the first chapter. The nature of spontaneous symmetry breakdown is illustrated early on by the example of superfluid helium. Dimensional regularization is used throughout, and the renormalization group is introduced as soon as renormalization is discussed. The final chapter on quantum electro-dynamics does contain some calculations whose strong-interaction QCD (non-Abelian) counterparts are discussed. In general, the material which is included is thoroughly covered starting from first principles. This has made for a rather long volume even though its range is limited. Perhaps someday I will write a second volume to make a whole book, but the remaining topics are treated in the references which are listed at the end of this volume.

A set of problems appears at the end of each chapter. The role of these problems should be explained. Many are exercises (some simple, some not) which help the reader gain facility with the ideas and techniques introduced in the text. Other problems review material which is assumed to be known in the text such as those which describe determinants at the end of Chapter 1 and special relativity at the end of Chapter 3.