One of a small group of the best Buddhist books I own. Tulku Urgyen was at hand when my teacher Mipham Rinpoche taught his first seminary program as an advisor, as he as guided many Buddhist teachers. Especially for vayrayana students, this is a book of unparalleled clarity, patience, loving guidance on how to further open your mind to effortless clarity, which comes at first in occasional glimpses of clarity which can often be puzzling at first, as we expect things to be conceptually clear. If you have not a realized teacher who has already introduced you to the nature of mind, either save this for later, or read short sections at a time, with plenty of time to meditate and contemplate. It says in the preface that it has been edited "out of respect for the seal of secrecy," but even with the guidance of a teacher one needs to go gently into not turning the teachings here into something you can explain to someone. It would be like trying to drive standard transmission without help near a cliff, thinking you have read what the clutch is for, so you do not need help!
Any sentence can be misunderstood, such as "do not do anything to your natural state." That in no way means you are making progress when you do whatever you feel like doing, and are content with being that way. It is a tip for finding the middle ground between too tight and too loose, and how to gradually sense where you are and what mind is. When I travel it is with deep regret that I cannot always carry both volumes because I am carrying other works of masters. His two sons are also great masters, which is evidence of how good a teacher and father he was. I listed that I have read it twice. I do not know. Some sections I have probably read ten times.