I have never read Rick Stack's book, but I have read William Buhlman and Robert Monroe and they basically say the same things. It makes sense though when you think about it. They say the physical world we are in now is the densest of all planes and that it takes a while for thoughts to manifest. However, in the higher planes, thoughts form instantly and are a direct projection of what we are thinking at the time.

I remember one of my friends was telling me about this horrible nightmare she had once. She said she heard loud noises and her body was paralyzed and she couldn't move and she looked over and saw herself in the bed next to her but it was herself as a rotting corpse. Luckily I knew about OBE's and asked her if she was afraid she was dying when all the strange sensations were happening to her and she said yes. I told her she most likely had an OBE and that her fear of death manifested into actually SEEING herself as a rotting corpse. She didn't believe me and said it was simply a nightmare. It could have very well been, but the physical sensations she described sound a lot like an OBE to me. I just wanted to share :)