Arthur C. Clarke and Stephen Baxter, the "Time Odyssey" trilogy comprising Time's Eye (2004), Sunstorm (2005) and Firstborn (2008). This is billed as an orthogonal offshoot, neither sequel nor prequel, of the utterly famous 2001: A Space Odyssey scenario. In characteristic Baxter-series fashion -- and I don't detect any stylistic input from Clarke, though it's true to his themes -- the books develop in different directions. They're linked by a continuing heroine and the premise that the "Firstborn" intelligences who kicked off 2001 with their helpful spot of Uplift have, in this alternate world, decided from the outset that humanity should not be encouraged but eliminated. In Time's Eye they fudge up a world of shuffled temporal geography after the fashion of Fred Hoyle's October the First Is Too Late. The resulting patchwork planet forms a game-board where -- with a very little high-tech input from the crews of a 2037 UN helicopter and Russian Soyuz lander caught up in the "Discontinuity" -- Alexander the Great and a small British force from 1885 Afghanistan are pitted against the Mongol horde of Genghis Khan. (A young Kipling appears as embedded reporter among the British Raj troops.) The Khan's nastiness is effectively and memorably shown, and the final clash ingeniously stage-managed with the help of one barely believable act of self-sacrifice. Eventually it emerges that this scrambled Earth, named Mir by one of the Russians, is a construct in a parallel universe or some such; the 2037 "present day" Earth is unaffected. The Firstborn, whose hovering Eyes are everywhere on Mir, appear to gain nothing from this immense exercise but the joy of voyeurism. What may be a friendlier faction of enigmatic ancients returns our protagonist Bisesa to her familiar 2037 London for Sunstorm.
Now, thanks to a Firstborn plan initiated two millennia past, the Sun is behaving badly and in just a few years will erase all life from Earth. There is much technological relish in the design and construction of an immense space shield at the Lagrange point L1. Thematic echo and inverted echo of 2001: the chatty AI built into the shield does not reveal all she knows about the extent of the coming disaster, for fear of reducing humanity to such despair that we give up trying. But she has a heroically self-sacrificing plan.... Speaking of the "she" pronoun, the redressing of traditional gender imbalance in Sunstorm is very determined, with a female UK Astronomer Royal, a female Mayor of London, a female European Prime Minister, a female (and Aboriginal) Australian prime minister, and a female (and Hispanic) US President. I don't think there's a female Pope, but Vatican City gets destroyed by a random act of senseless terrorism well before the day of sunstorm, which probably brought a thin smile to Sir Arthur's lips. Earth duly survives, though with significant losses, and only a carping critic would wonder why the Firstborn didn't simply clobber our planet with a modest dinosaur-killer in, say, 1900 rather than laboriously setting up this solar flare and mass ejection by dropping something the size of Jupiter into the Sun circa 4BC.
Twirling their moustachios in frustration at the failure of this equivalent of trapping the victim in a cellar that's slowly, very slowly, filling with water from a dripping tap, the bad guys finally decide to stop pussyfooting around in Firstborn. Here comes the unimaginably devastating Q-bomb! Unhurriedly and suspensefully this makes its inexorable passage from Jupiter towards a doomsday impact with Earth: bullets won't stop it, nor fusion warheads, nor engineered asteroid collisions. But -- again shades of 2001 -- excavations on Mars have revealed another Firstborn artefact, a trapped Eye. Eyes, like those famous monoliths, are not only sentinels but communicators and gateways: Bisesa goes looking for help, and finds it in an odd place. (A further feminist note: the chair of the World Space Council, the captain of Earth's sole antimatter-driven space warship, and the last surviving Old Martian are also female.) It's pretty well told, despite requiring substantially more than trace quantities of the miracle element handwavium to make everything come out right. After the Get Out of Doomsday Free card is finally dealt from the bottom of the deck, loose ends are tied and we move to -- in John Clute's phrase -- a slingshot ending, with a bracing touch of Baxterian chill about what happens in the long run.
I rather enjoyed these books. Time's Eye has lashings of plausible historical research. Sunstorm is the strongest of the three, balancing a extinction threat based on solid science with a last-ditch countermeasure in which it's possible to believe. Conversely, the Q-bomb of Firstborn is technology all too indistinguishable from magic. When, as it were, the correct incantation is addressed to the correct god, the menace magically slinks away. It also seems a too-obvious plot convenience that Eyes -- the devices, remember, of the Enemy -- should repeatedly transmit Bisesa to places where she needs to be, not because she's mastered their operation or even begun to comprehend it, but because someone out there apparently likes her. One might almost postulate some omnipotent Author....