If you recognise Sylvia Engdahl's name, you're probably familiar with her thought-provoking and highly unusual young-adult science fiction. With Stewards of the Flame, she explores two brave new worlds: adult science fiction and parapsychology. Don't let the new-age associations deter you: like its predecessors, Stewards brims with startlingly intelligent, well-developed ideas about mankind, civilization and technology.

And in case you were worried, yes, there is a plot. The book opens when Jesse Sanders, starship captain, awakens in a hospital after a night of hard drinking. On the planet Undine, any form of addiction is considered a health condition to be treated and forcibly cured. Jesse is neither an alcoholic nor a willing patient, but he soon discovers that he is a prisoner of the hospital.

Fortunately, he's not the only one on the planet dissatisfied with its policies; there's an entire subversive organisation on his side. The Stewards of the Flame, as they call themselves, are more than political dissidents: they have been secretly developing paranormal mental abilities innate to humanity, using their minds to regulate pain, communicate and heal. When asked to join them, Jesse plunges into an adventure that takes him far into his own mind, into the hospital's stasis chambers in which brain-dead bodies rest on artificial life support forever, and beyond.

Despite its distant setting, Stewards of the Flame presents a frighteningly plausible scenario in which all human rights and possibilities are stunted by the fear of death. Although Engdahl comes down clearly in favour of her idealised Stewards, she is persuasive rather than dogmatic and writes with intelligence and vigour, whether she is exploring the human mind or critiquing Undine's medical dystopia. An afterword reveals that Undine is rooted in current medical practices.

At well over 400 pages, the book is occasionally a little unwieldy, and as with the author's other books, ideas sometimes overshadow both action and character. Jesse is a likable hero whose initial scepticism and resistance to the Stewards is wholly believable, but his romance with group member Carla has too little basis to justify its centrality -- and too little sexual tension to be juicy reading.

Engdahl insists, perhaps because of the link she establishes between sexuality and telepathy, that this is not a young-adult book. Its length, complexity and lack of cool aliens also mean that it is unlikely to appeal to mainstream SF readers. Rather, this is mind-stretching speculative fiction for the thinking person.

A small spoiler: the ending of Stewards of the Flame is one of the best endings I've ever come across. It is absolutely right for the book.