The Last Theorem by Arthur C. Clarke and Frederik Pohl
HarperVoyager, £18.99; 299pp Buy the book here

The Night Sessions by Ken MacLeod
Orbit, £18.99; 324pp Buy the book here

The Steel Remains by Richard Morgan
Gollancz, £12.99; 345pp Buy the book here

To write his final novel, Arthur C. Clarke teamed up with his fellow grand master (a title awarded by the Science Fiction Writers of America), Frederik Pohl.

There is an old idea at the core of The Last Theorem: an incomprehensibly advanced alien race notices that we have nuclear weapons (the brilliant flash of detonations eventually reaches distant worlds) and decides to exterminate humankind before we can become a serious threat.

The book is structured like a fictional biography, with breaks for cartoony sketches of various aliens in outer space. Our hero, Ranjit Subramanian, is an intelligent, good-looking boy whose interest in mathematics, combined with solitary confinement (when he is mistaken for a terrorist) results in his proving Fermat's Last Theorem without recourse to methods that were not available to Fermat himself. This assures his fame and brings him into contact with powerful people, but has little connection with the rest of the plot.

Several of Clarke's scientific hobbyhorses are trotted out, most notably the construction of a space elevator, based in his beloved Sri Lanka, even though the authors had to change the location of the Equator to make that situation likely. Pohl demonstrates his trademark cynical humour and mathematical party tricks, and there are also speculations on subjects from religion to virtual reality. There are things to enjoy, but, disappointingly, they don't really add up.

Space elevators feature in The Night Sessions, Ken MacLeod's gripping and clever near-future thriller. It's set some decades after the last of the Faith Wars that followed 9/11, in the wake of the revulsion over the extremes of fundamentalism that led to the Great Rejection. Religions, while not banned, attract only a small minority of citizens as a unified, secular world works together to stop global warming and move out into space.

Then, in Edinburgh, a Roman Catholic priest dies when his flat is bombed. Soon after, a bishop is assassinated, and it seems that a new age of religious warfare is about to begin, with roots going back to the 17th-century Scottish Covenant, and branches reaching up to the ongoing construction of two space elevators, pillars to Heaven that could come crashing down on humanity's best hopes for survival.

Earlier this year, Richard Morgan won the Arthur C. Clarke Award for Black Man, the most recent of his powerful, noir-ish science-fiction novels. The Steel Remains is just as strong, and even darker, but moves into different territory. Morgan has taken traditional sword and sorcery tropes and given them a hard, contemporary kick. The main protagonist is respected for his heroic exploits with his miraculous sword, but, in a homophobic society, he is also despised as a degenerate. The sex scenes are as explicit as the many violent battles, and a miasma of rage at the general unfairness of life fairly rises off the page. The antithesis of the cosy fairytale, this is one for big boys.

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