AS A READER of speculative fiction, I am a seasoned traveler in unfamiliar landscapes, accustomed to figuring out new language and customs as I negotiate through the terrain of a plot. An SF novel can seem a great deal like a spirited travelogue, with the author serving as tour guide. (Presumably that sense of things is what drove Diana Wynne Jones to write The Tough Guide to Fantasy Land; quest novels, with their epic journeys, are particularly like travelogues.) Some authors are solicitous, almost obtrusive tour guides, offering maps, glossaries, family trees, appendices with supplementary history, or outright infodumps at relevant opportunities. For example, in the classic Nine Princes in Amber, Roger Zelazny provides a full-service introduction to the Amber universe with an amnesiac narrator, allowing the reader to learn about Amber as the protagonist does.

In contrast, Hannu Rajaniemi, architect of a future that bears a strong resemblance to fantasy (and who, incidentally, claims Zelazny as an influence), is decidedly more reserved in his involvement; he’s a travel agent who will arrange your journey to the smallest detail, but once you’ve set off, he’s unlikely to provide you with any further assistance, other than making sure you arrive at your destination. What that destination might be may not be discernable for some time, even while en route. Rajaniemi, a Finnish physicist who runs an A.I. think tank in Edinburgh and writes exquisitely in a language that presumably wasn’t his first, may be doing us the courtesy of respecting our intelligence. He simply assumes we’ll catch up. Readers (myself among them) may therefore come to the end of Rajaniemi’s new novel, The Fractal Prince, feeling more than a little lost, and perhaps somewhat inadequate as a result. Here’s a sample piece of action from partway through the book, a space battle that seems to require somewhat more knowledge of string theory (Rajaniemi’s specialty) than even your typical science-savvy SF reader has, to parse:

The Sobornost fleet falls upon the quantum filth from the shadow of the cosmic string.           

The warmind coordinates the attack from the battle vir…. He sees through the eyes of all of his copybrothers, from the lowest nanomissile warhead mind to his own elevated branch in the oblast ship.

He needs all of them to surf the deficit angle that the string cuts out of spacetime, a gravitational lensing effect that makes the zoku see double. A scar in the vacuum left by the Spike, the string is less than a femtometer thick, ten kilometers long, looped — and more massive than Earth, accreting clouds of hydrogen and dust like flesh around a bone.

A bit more explication of the physics involved (“surfing the deficit angle”?) would really be helpful, more helpful than the description of the Schrödinger’s Cat problem given earlier in the book — that thought experiment is such a familiar part of the geek zeitgeist that explaining it is superfluous.

While still requiring the occasional headscratch, the previous book in the series, the brilliant The Quantum Thief, was actually quite straightforward in its plot. In the far future, millions of versions of the Lupinesque t...