In the end, for better or worse, this is a novel held together by its author’s moral vision. Transition may boast a postmodern plethora of worlds, but it offers a single old-fashioned world-view which all this random rattling about paradoxically reveals... This is a thriller with a conscience, decent and timely, even if, amid all the blood and thunder, it sounds what can seem an incongruously still small voice.

Despite being published without the M in the author’s name - except in the US - this Iain Banks novel features parallel worlds, and flitting between them, and has as a plot point the existence or not of alien intelligences somewhere out there. As such it can scarcely be described as mainstream. But then early Iain “no M” Banks offerings (Walking On Glass, The Bridge, Canal Dreams) were suffused with SFness and/or sensibility (The Wasp Factory.)

Transition does, though, signal its literariness from the outset – its strapline is “based on a false story” and the first words of its prologue are, “Apparently I am what is known as an unreliable narrator.” There is, too, a high degree of characterisation throughout even though, with the aid of a drug known as septus, most of its main characters can flit from one body to another. In typical Banksian fashion there is a shadowy organisation - here known as l’Expédience, or the Concern (which last is a pun) based on a world unusually known as Calbefraques rather than Earth - in charge of the use and distribution of septus and of recruitment to and training for the transition process.

I did notice that while at one point it is said that there has to be a recipient body for transitioning to take place - the one left behind has only rudimentary function as a husk - later transitions to uninhabited worlds do take place without added explanation.

The narrative is divided between various viewpoint personalities, Patient 8262, who is in hiding in a hospital in a country where the local language is not his own, The Transitionary, who may be an earlier incarnation of Patient 8262, Adrian, a former drug dealer turned hedge fund manager, Madame d’Ortolan, foremost member of the Concern’s ruling council, The Philosopher, a legal torturer, and occasional others. The Transitionary’s is a first person present tense narrative, others are past tense, sometimes first, sometimes third person. The most intriguing character is the rather prosaically named Mrs Mulverhill – who is not married, merely likes the name.

In the sort of inversion beloved of SF authors one of the parallel worlds has a set of Christian fanatics pitted against the state and indulging in suicide bombings and the like. The scenario gives Banks the opportunity to riff on how proportionate a response society ought to have to terrorism and on the (in)efficacy of torture. One of his characters also skewers “the invisible hand.”

Devotees of Iain M Banks will probably find this a treat. Followers of his M-less namesake ought also to find enough in it to satisfy them.