T'ai Chi, The Supreme Ultimate Exercise for Health, Sport and Self-Defense
Authors: Cheng Man-Ch'ing and Robert W. Smith
Note: excellent photos and explanations of form and brief history, principles, push hands

The Essence of T'ai Chi Ch'uan, The Literary Tradition
Authors: Benjamin Pang Jeng Lo, Martin Inn, Robert Amacker, Susan Foe
Note: translation of classics ~ pure poetry for contemplation and investigation

The Essence and Applications of Taijiquan
Author: Yang Chengfu
Note: form and function explained with accompanied photos

Cheng Tzu's Thirteen Treatises on T'ai Chi Ch'uan
Translation by: Benjamin Pan Jeng Lo and Martin Inn
Note: "required reading"

The Tao of Tai-Chi Chuan, Way to Rejuvenation
Author: Jou, Tsung Hwa
Note: well-respected author and teacher whose book is dedicated to "the friendship of Chinese and American peoples." history, philosophy, meditation, drawings and photos

Cheng Man-Ch'ing, Master of Five Excellences
Translation by: Mark Hennessy
Note: insight into the life of a great 20th century "Renaissance man"

Mastering Yang Style Taijiquan
Author: Fu Zhongwen
Note: detailed "long form" explanation with photos, history and principles

There Are No Secrets, Professor Cheng Man-ch'ing and his Tai Chi Chuan
Author: Wolfe Lowenthal
Note: photos and delightful reading that will inspire and make you smile!

Gateway to the Miraculous, Further Explorations in the Tao of Cheng Man-ch'ing
Author: Wolfe Lowenthal
Note: Lowenthal was a student of Man-ch'ing in NY for many years ~ you likely will enjoy the school's website and newsletter Long River Tai Chi Circle

https://www.iritaichi.org/posts.html 

Posts online by Martin Inn, co-founder of the Inner Research Institute San Francisco

by Robert Amacker (Author)  Format: Kindle Edition 

Other of the author's writings found here: https://whitecrowtaiji.com/about/

These are but a few, in no particular order, of many elucidations on taiji ~ We welcome your suggestions and recommendations!