This book considers recent developments in very high-order accurate numerical discretization techniques for partial differential equations. Primary attention is given to the equations of computational fluid dynamics with additional consideration given to the Hamilton-Jacobi, Helmholtz, and elasticity equations. This book should be of particular relevance to those readers with an interest in numerical discretization techniques which generalize to very high-order accuracy. The volume consists of five articles prepared by leading specialists covering the following specific topics: high-order finite volume discretization via essentially non-oscillatory (ENO) and weighted essentially oscillatory (WENO) reconstruction, the discontinuous Galerkin method, the Galerkin least-squares method, spectral and $hp$-finite element methods, and the mortar finite element method. Implementational and efficiency issues associated with each method are discussed throughout the book.