I have really enjoyed and benefitted from reading and studying the
following two books:
Combat Techniques of Taiji, Xing Yi, and Bagua: Principles and Practices of Internal Martial Arts. By Lu Shengli. Translated and Edited by Zhang Yun and Susan Darley. Berkeley, California, Blue Snake Books, 2006. 369 pages. ISBN:9583941452. MGC. General history and principles of 3 internal arts, basic movements, basic gongfu training techniques, and a detailed description with photographs of the Sxteen-Posture form (pp. 231-356).
Complete Kickboxing: The Fighter's Ultimate Guide to Techniques, Concepts, Strategy for Sparring and Competition. By Martina Sprague and Keith Livingston. Wethersfield, Connecticut, 2004. Index, 479 pages. ISBN: 1880336847. Excellent training techniques and fighting tactics.