"What if?" is, in a sense, the question asked by all fiction. But it's especially the province of that now-burgeoning sub-genre known as alternate history. One would think that alternate history, like its progenitor, science fiction, would be a glittering basket of exotic prose jewels, that it would be difficult to fall into a trap, a trope, a routine when it comes to fiction that explicitly airs the inquiry behind so many of this world's books. But it's the case here, as everywhere, that habit settles in and what could be quickly evolves into what is, and what is quickly becomes what was. The fiction of today, be it alternate history, science fiction or literature usually decides that to achieve success one must emulate the formof the successful, rather than the innovative spirit of the successful. So alternate history gets its formula; choose a breakpoint in history and tweak it, then spin out a new world with the same old characters, the same old famous men and women, their parts and paths now recast. This is not to say that the result is bad alternate history or bad fiction. There's a lot of fun to be had for the reader and writer in these recast realities. But alternate history offers some wonderful opportunities that few writers seem to have followed.

It's the meta-fictional possibilities that seem the most potentially powerful. If one is to create literature about another history, why not create literature from another history? Kim Stanley Robinson's 'The Years of Rice and Salt' is that work, that artifact of another timeline. Robinson's break-point is the Black Plague, and this novel is the product of a world in which that Plague killed 99% of the population of Europe. The resulting document is a hermetic work, self-contained but not self-serving. The world that results from Robinson's historical change is dominated by the Islamic and Buddhist civilizations that are allowed to flower in the absence of Christianity. The document that we're given in this novel is the product of that world. The prose, the construction, the concerns, the characters, the very cleverness of the work itself all have their origin in a world that only Robinson has visited. The lessons it teaches are the lessons of the world it describes. The power it derives is from the purity of Robinson's execution. And that power is nothing less than astonishing.

Described from the outside, from the vantage point of our history, 'The Years of Rice and Salt' reads most like a fantasy, because the world described by Robinson is quite properly nothing like ours. Don't expect to find Abraham Lincoln in a turban on a dhow in the Mississippi. In fact, there is only one actual historical figure after the breakpoint, and I suspect very few readers will recognize that figure. Robinson's world is entirely another, and that's why it reads like a brilliantly imagined fantasy, diamond-hard, perfect. But most importantly for the reader, it's powerfully entertaining and affecting.

'The Years of Rice and Salt' unrolls as a series of novellas. Each novella tells the story of at least two and sometimes three characters who are given names beginning with B, K, and I. The novellas follow one another through the centuries, starting with the breakpoint as Bold, a barbarian on the steppes of Asia, finds the villages decimated by the plague. At the end of each tale, the characters die and meet again in the bardo, the Buddhist afterlife where they await rebirth and discuss the lessons they might have learned from their previous existence. Each novella is richly imagined and gripping; only in one very short passage does Robinson resort to moving the action along in an obvious "thisworldly" manner. As the novellas progress from the past towards the present, the world described becomes stranger and stranger to the readers of this world. But so strong is Robinson's imagination, it will seem no less real.

Robinson's astonishing achievement allows him to tell a variety of stories; love, war, discovery and betrayal mingle in his narratives. B, K and I return and the reader will delight as each is discovered or revealed in Robinson's complex tales. Robinson eschews all the easy routes in this book. There are no monsters, no aliens, and no cameo appearances. There are no human-bull hybrids roaming in a Grecian island theme park. In this regard the novel is on the ascetic side. Robinson reserves his strength for the emotions that affect a reader most powerfully. He manages to create another world, a fantasy so tightly knit it should draw comparisons to 'The Lord of the Rings', and within that fantasy, he manages to evoke feelings of nostalgia and wistfulness so pure they ring true to readers in this world.

But beyond the artifact of the novel itself, more questions are posed. A very real breakpoint in recent history follows from the events of September 11, 2001. As horrific as the events of that date -- and those to follow -- were, we cannot ignore the fact that they have truly and deeply affected us. The most apparent change is a rising awareness of the Islamic religion. Much of that awareness in the West centers around fear. Robinson's work, which takes the Islamic religion as one of the focal points around which it creates a new world, was fortunately written before the 9/11 breakpoint. The result is that Robinson offers a dispassionate vision of Islam, untainted by the intense and often rabid feelings that currently dominate discourse.

Robinson also offers substantive visions of the development of science and the part played by women in history. His characters, re-incarnated as men, women and even, in one case, a tiger, shift, change, learn and grow through their lives. For one moment, he shows a progressive Islamic faith that affirms the power and import of women. And in one portion set in China, he creates Widow Kang, who by her own observations and collection of other women's observations, drives in a stake around which a more equal world is created.

Taking the reader through 'The Years of Rice and Salt' is Robinson's prose and poetry. The prose is varied and compelling, perfectly pitched to each period in which it is to have originated. This gives the book a vitality and variety that alternate history often lacks. Robinson's poetry is smart, touching and very effective. In this world, he's written quite a bit of poetry and based on the quality of what we encounter here, it's surprising that he hasn't put together a collection.

The power of the cumulative lives that Robinson portrays, the sequential stories he tells, is sneaky and strong. Readers will be pulled by the adventure and imagination he displays and not realize the more subtle psychological and philosophical effects the novel achieves until well into the narrative. The inevitable effect of reading this novel is to regard the world around you in terms of the world it describes. The shift is slow and unstoppable. Readers will look for those around them whom they might expect to meet in the bardo. Moreover, Robinson is an optimist. This novel is ultimately a utopian novel and the vision it offers is convincingly, overwhelmingly positive. Starting out so far in the past, finishing up shortly in the future, 'The Years and Rice Salt' is both a world unto itself and an artifact from that world. It's the best years of our lives -- the lives we've never lived, the lives we'll never know.