This book is not just about math or computing or applications, but about all three-in other words, computational science. Each section of the first six chapters is motivated by a specific application. The author applies a model, selects a numerical method, implements computer simulations, and assesses the results. These chapters include an abundance of MATLAB code. The last four chapters focus on multiprocessing algorithms implemented using message passing interface (MPI). These chapters include Fortran 9x codes and revisit the applications of the previous chapters from a parallel implementation perspective. MATLAB, Fortran, and C++ codes are available for download from the Internet.