This is a softcover reprint of a very popular hardcover edition, published in 1999. An account is given of the state of the art of numerical methods employed in computational fluid dynamics. Numerical principles are treated in detail, using elementary methods. Attention is given to difficulties arising from geometric complexity of the flow domain. Uniform accuracy for singular perturbation problems is studied, pointing the way to accurate computation of flows at high Reynolds number. Unified methods for compressible and incompressible flows are discussed, as well as the shallow-water equations. A basic introduction is given to efficient iterative solution methods.