This is a Dover reprint of a book first published by Academic Press in 1975. The Telegraphic Review by Ih-Ching Hsu appeared in the January 1976 issue of the Monthly:
Exploits classical results (the three different types of PDEs, their Dirichlet and Cauchy problems, etc.) using non-traditional methods, at a level of abstraction appearing in modern research. Fourier transformation of distributions is used systematically. Truly introductory, it nonetheless touches on various important topics, such as potential theory, Dirac equations, random walks, continuous semigroups of operators. An excellent book for modern analysts who appreciate rich roots in the past.