Strange experiences in fiction

I remember reading a science fiction novel some years ago (I think that it was 'Dreamside' by Graham Joyce) in which a group of participants in an experimental dream project start to experience a terrifying regression in which they apparently awaken from a dream, only to discover that they have awoken into another dream. The process continues, and the implication is that one could be trapped in this. I have never come across any references to this in reality, and would be interested if anyone has ever had a similar experience, or knows of any research into it. I have had the occasional lucid dream, but I tend to wake up fairly quickly once I realise that I am dreaming.
Whilst discussing science fiction, I will mention my own love of novels based upon alternative versions of ourselves interacting and entering one another's worlds, either through psychic interaction or physically. John Wyndham wrote a short story on this theme back in the 1950s, where I think a machine provided the means of transfer. Someone was paid a visit by a parallel self to advise him to marry an ex-girlfriend who was his wife in the parallel world.
There are two wonderful more recent novels on this theme, using the Many Worlds Interpretation of Quantum Theory as the explanation. These are 'Infinity's Web' by Sheila Finch, and 'Lost Futures' by Lisa Tuttle'. Ian Watson has also written novels touching on these themes.
Finally, an interesting description of an experience from the autobiography of a mystical writer called Elisabeth Haitch. She was (I think) Hungarian, and must have written her book ('Initiation') around the 1970s. She is describing events in the first half of the 20th Century. She apparently started to relive memories of a past life in Ancient Egypt, when she was initiated. There are similarities to the writings of Joan Grant. I found references to her book on the Internet - mostly criticisms that what she describes is unlike what we know of Ancient Egypt. But the idea that interested me, and which touches on the nature of time, involves her description of her initiation. She describes tests, in which she experienced situations that could be failed in some way. I think that the tests involved the traditional elements. They were experienced in a dream like state of trance. But if you 'failed' the test (were ruled by one's passions, for instance), you would live the experience out in historical time, thousands of years later.