Crystal Cave is the first of the Rangjung Yeshe restricted texts. It was all translated by Erik Pema Kunzang. I wish someone could sponsor a new edition of this wonderful book.Pero wrote: Another book that I though was amazing is Dilgo Khyentse's Crystal Cave. I've had a chance to look at it when I was in Yeselling (Austrian Ling of DC). It's a actually a collection of various teachings. I think I remember one member of E-Sangha saying it was mind blowing and after reading parts of it I could see why he thought that way. They sell it at Rangjung Yeshe but unfortunatelly, this one is restricted even more. Not only do you need direct introduction but also need finished preliminaries.