The experiment goes to plan, with poltergeist activity and disembodied messages, all scientifically recorded. Sam's theory appears conclusive - that ghosts are created by the people who see them.

But then several disturbing and inexplicable events happen which lead them to believe that "Adam" has somehow taken on a life of his own, and is now beyond their control. Perhaps even a threat to all of them...

When the definitive history of science in the 20th century is written, the conclusion may be that the greatest discovery was not the computer, the atom bomb or the television but the fact that we know nothing for certain at all. Heisenberg's Uncertainty Principal and the laws of quantum physics have undermined the simple, empirical world in which our Victorian ancestors lived. Despite its title, it is science rather than the supernatural which is the basis of David Ambrose's new novel, Superstition.

In his prologue Ambrose introduces Sam Towne, a university researcher into paranormal phenomena, entering the house of a man he does not know, who, it now appears, is the husband of the woman he loves.

Except that when he meets her, she is not the same woman. We then jump back a year, to reporter Joanna Cross, who is set on exposing fraud in the world of supposed psychics. Indirectly, her work leads her into contact with Towne and the suggestion that she monitor an experiment in which he wants to create a ghost.

The idea is that a group of people can conjure up a personality who will then respond to their questions. The "ghost" the group agrees to create is pure fiction, invented by committee: a young American who lived in revolutionary France and associated with the great minds and mystics at the close of the 18th century. When their "seance" table starts to emit knocking noises in answer to their questions, they react with astonishment and delight. But that soon turns to horror as, one by one, members of the group suffer violent deaths. The "ghost" refuses to be laid.

The inevitable question is: have they unleashed from within themselves a psychic power they cannot control or have they unwittingly summoned a real ghost? That possibility becomes frighteningly much more plausible when Joanna stumbles across his grave.

Ambrose writes with verve and lucidity, carrying the reader with him every step of the way. Superstition is a clever book but an intelligent one too, tightly plotted, intellectually teasing and a riveting read to the final, satisfying full stop.

No movie or book can be taken as evidential proof that a world of spirit exists parallel with ours. But paranormal investigators press on, peering into the invisible. In imitation of a real-life famous experiment conducted 20 years ago, when parapsychologists in Toronto claimed they'd invented a ghost named Philip, a team of Manhattanites decides here to invent its own ghost, or thought-form, by pooling their mental energies and focusing them on a fictitious English-speaking character named Adam Wyatt, whose life they write, placing it in the well-researched period of the French Revolution. As psychologist Sam Towne and his group of six volunteers (including a magazine reporter) go on meeting, they become so familiar with Adam that when he actually begins table-rapping, as presumably did Philip, they're naturally elated and begin asking him all sorts of questions. Many he can't answer because they can't answer the questions: he knows only what they know, being made of their thoughts. But, as it happens, he's also made of their darker natures, and the time comes when Adam himself begins to create an alien universe parallel with their own and starts sucking them into it by leading them to their deaths. As always, Ambrose misleads us toward one climax, only to substitute a hugely inventive, jaw-dropping, bittersweet alternate climax.

Featuring a cast of warmly attractive adult characters and no human villain in sight, the latest from Ambrose has been sold to Tri-Star films for one million. If the film sticks to it's terrific ending, instead of going soft like Ghost, this could make one of the scariest, brainiest, most memorable love stories ever made about the unseen. (Film rights to Interscope/Columbia/Tri-Star).