Book excerpt: This book aims to provide an example-based education in numerical methods for atomistic and continuum simulations of systems at and away from equilibrium. The focus is on nonequilibrium systems, stressing the use of tools from dynamical systems theory for their analysis. Lyapunov instability and fractal dimensionality are introduced and algorithms for their analysis are detailed. The book is intended to be self-contained and accessible to students who are comfortable with calculus and differential equations.The wide range of topics covered will provide students, researchers and academics with effective tools for formulating and solving interesting problems, both atomistic and continuum. The detailed description of the use of thermostats to control nonequilibrium systems will help readers in writing their own programs rather than being saddled with packaged software.