I agree you should read Stephen Laberges book. But if you want to go even deeper on the subject and are serious about LD'ing you could try some books about "Dream Yoga". (which btw. have nothing to do with putting your limbs in strange and abnormal positions)

"The Tibetan Yogas of Dream and Sleep by Tenzin Wangyal Rinpoche and Mark Dahlby"

"Dream Yoga and the practice of natural light by C. Namkhai Norbu, edited by Michael Katz"

The first one is the eastern equivalent of Stephen Laberges book, but written for westerners. The second is also highly recommended.