Nirvana — An Occult Experience by George Arundale
http://users.ez2.net/nick29/theosophy/naoe-index.htmThis book by Mr. Arundale is the story of his trips into Nirvana each night as he sleeps, and then his travels back to the physical world every morning when he awakes. It also describes how his reaching "Nirvanic consciousness" effects him while he is awake here in the physical world.
I enjoyed the book, because it is the only book I know that goes into detail about what Nirvana really is. The parts of the book I did not like are his continual use of Christian terms, which Buddhists and Hindus will find very distracting.
It needs to be mentioned that the nature of Nirvana is a hot topic in Buddhism -- this and one other topic always start an argument. Is Nirvana a place? Is Nirvana only a state of mind? Mr. Arundale gives his answer very clearly.