Boundary Value Problems, Fourth Edition is a revision of a textbook for an introductory course on boundary value problems. Powers has written an overview of solving partial differential equations by the methods of separation of variables. The text is comprised of five parts.
I have been teaching undergraduate Partial Differential Equations for 31 years. I have tried various textbooks, including classics such as, for example, Brown and Churchill, and other well-known texts, for instance, by Colton, Jeffrey, Pinsky, Duchateu and Zachman, and others. After each such experiment I come back to David L. Powers. It is a perfect undergraduate text on boundary value problems, Fourier methods, and partial differential equations. The level is just right - not too difficult yet not too trivial. The selection of problems is great, with varying level of difficulty. The author's writing is clear and understandable even by medium-level undergraduates.
I have just reread the textbook in preparation for my spring course, so I am listing the date of finishing as December 20, 2014, although the first time I read this book was in 1989.
Of course, the text would be too low level for a graduate course, but it provides a wonderfully clear introduction to Fourier methods. Highly recommended!