From the reviews of the earlier editions:

?An excellent second-reading text. Should be accessible to any mathematician. Highly recommended.? ? The Mathematical Gazette ?An excellent text upon which to build and introduction to partial differential equations at the graduate level. In addition?recommended for the nonspecialist.? ? American Mathematical Monthly Partial Differential Equations is a very well accepted introduction to the subject. In it, the author identifies the significant aspects of the theory and explores them with a limited amount of machinery from mathematical analysis. Now, in this fourth edition, the book has again been updated with an additional chapter on Lewy?s example of a linear equation with solutions.