"New Engineering Mathematics Volume III" deals with some of the more advanced and specialized topics in higher applied mathematics i.e. partial differential equations, "Fourier" series, boundary value problems, Fourier transforms and Z-transforms. In the chapter on partial differential equations, methods of formulating practical problems in terms of partial differential equations, finding their solutions and physically interpreting the results are discussed. "Fourier" series, their different possible forms and practical harmonic analysis are introduced. The classical boundary value problems - wave equation and heat equation - and their solutions using Fourier series method are discussed. The chapter on Fourier transforms contains the applications of Fourier integral theorem, convolution theorem and related concepts. A detailed treatment of Z-transforms, its general properties and applications to solutions of difference equations is given in the last chapter.