This second volume of Elementary Particle Physics, "Foundations of the Standard Model", concentrates on the main aspects of the Standard Model by addressing developments from its establishments to recent progress and some future prospects. Two subjects are clearly separated which cover dynamics of the electroweak and strong interactions, but basso continuo throughout the book is a bridge between theory and experiments. All the basic formulas are derived from the first principle, and corrections to meet the experimental accuracy are explained. This volume is a logical step up from volume I but can also be considered and used as an independent monograph for high energy and theoretical physicists, as well as astronomers, graduate students and lecturers in physics.