I had the pleasure of having both Prof. Berg and Prof. Samuelson as instructors while I was a mathematics major at Stanford. Neither of them taught PDEs while I was there, alas, for I think I would have enjoyed the subject a lot more at the time (I love it now, but really disliked it then). This book is somewhat old-fashioned in its approach, so don't read it for flashy diagrams and so forth. But there's a lot of good, solid rigor and explication in the somewhat dense text. Berg & Samuelson focus a lot on Fourier series as a tool to acquiring solutions to various families of PDEs. The standard examples are used as pedagogical touchpoints, including initial-value problems like the heated plate, and boundary-value problems such as vibrational modes in 1D and 2D.