​Kang-Sin Choi is assistant professor division chair of the Scranton Honors Program at Ewha Womans University, Seoul, Rep. of Korea. His research focuses on the Standard Model of particle physics and on how it can be completed by string theory.Jihn E. Kim is professor emeritus at the Seoul National University, Rep. of Korea. As theoretical physicist, his research focuses on fundamental particles and their interactions, based on symmetry principles and superstring models. Some of his research interests concentrate on neutral currents, neutrino magnetic moment, invisible axion, dark matter, grand unification, and the cosmological constant problem.

• Introduction and Summary.- Standard Model and Beyond.- Orbifolds.- Spinors.- Field Theoretic Orbifolds.- Quantization of Strings.- Strings on Orbifolds.- Formal Construction.- Non-prime Orbifolds.- Interactions on Orbifolds.- Effective Action.- Algebraic Structure.- Orbifold Phenomenology.- String Unification.- Smooth Compactification.- Flavor Physics.- Other Constructions.- A. Useful Tables for Model Building.