Huang Po seems to get the most attention but Garma C.C. Chang has a pretty helpful book on Zen, and RR used to refer to it often in his early talks. The book is a lot more straightforward and explanatory than Huang Po. Would any of you guys like to do a review of it?
The title is The Practice of Zen.
The links below will be helpful to students of Richard Rose
Digital version of Conquest of Illusion at Spiritual Books Worth Reading