Text presents the general properties of partial differential equations such as characteristics, domains of independence, and maximum principles. Solutions.
Here's a sample of other books in this Dover category
Introduction to Partial Differential Equations with Applications by E. C. Zachmanoglou, Dale W. Thoe This text explores the essentials of partial differential equations as applied to engineering and the physical sciences. Discusses ordinary differential equations, integral curves and surfaces of vector fields, the Cauchy-Kovalevsky theory, more. Problems and answer...
Lectures on Partial Differential Equations by I. G. Petrovsky Graduate-level exposition by noted Russian mathematician offers rigorous, readable coverage of classification of equations, hyperbolic equations, elliptic equations, and parabolic equations. Translated from the Russian by A. Shenitzer. 1954 edition.
Partial Differential Equations for Scientists and Engineers by Stanley J. Farlow Practical text shows how to formulate and solve partial differential equations. Coverage of diffusion-type problems, hyperbolic-type problems, elliptic-type problems, numerical and approximate methods. Solution guide available upon request. 1982 edition.