This book provides an overview of recent progress in computer simulations of non-perturbative phenomena in quantum field theory, particularly in the context of the lattice approach. It is a collection of extensive self-contained reviews of various subtopics, including algorithms, spectroscopy, finite temperature physics, Yukawa and chiral theories, bounds on the Higgs meson mass, the renormalization group, and weak decays of hadrons. Physicists with some knowledge of lattice gauge ideas should this book a useful and interesting source of information on the recent developments in the field.