Back in 2006 I wrote a book about my time with Master Liang. I include chapters on his writings as well as a guide to every posture of the Traditional Long Form along with text describing how to perform the postures.

While this will not take the place of a teacher it is a good reference for the form and contains chapters that describe Yang Taiji and why it is unique among exercise systems.

This link goes to the Canadian website.

And this link goes to the U.S. version.