"Differential equations (DE) are important because of their applications in fields like pure and applied mathematics, physics, engineering, biology, and economics. DE are the base of mathematical modelling applied to solve real-life problems that may not be solved directly. The subject is introduced in the school curriculum of mathematics and taught at undergraduate and graduate levels across India. The differential equation is taught as two courses - ordinary differential equations and partial differential equations. This book is designed to serve as a textbook for the first course on partial differential equations which is known as partial differential equations (PDE) or differential equations II in most of the Indian universities. There are numerous books in this area but most do not give adequate emphasis on the basic requirements of undergraduate students. The authors have utilized their teaching experience of several years to fill this gap. Special attention is paid to elementary partial differential equations and this book covers important techniques like Monge's method, Monge-Ampere type non-linear equations, reduction of first-order linear equation in canonical form, derivation of second-order quasi-linear equations, higher-order PDE with constants coefficients and their reduction to variable coefficients and so on. In addition to topical coverage, a large pool of solved and unsolved problems sets for hands-on practice is also provided"--