I once spotted Iain Banks on a wintry rush hour train in Glasgow, and immediately texted a friend who I knew was a fan. “Is he Iain Banks or Iain M Banks today?”, was the reply.

Today, he's both. Banks' new novel Transition is not only a story of moving between worlds, but also a melding of science fiction and mainstream genres. Even the marketing folk have embraced this theme, publishing Transition under the author's mainstream persona Iain Banks in the UK, and his SciFi twin Iain M Banks in the US.

Banks summons a blokey, non-academic crowd. The RBS Main Theatre is bustling with people who sit decisively in the folding seats, debating the relative coolness of The Wasp Factory vs Espedair Street.

After a deliberately dry introduction from novelist and chair Paul Johnson, Banks reads the prologue from his new novel. Like many novelists, Banks' performance doesn't do justice to his work. Transition's prose is tactile, complex and sensuous (I had a sneaky read in the bookshop), but Banks rushes through the reading, as though worried that the audience will become bored with the meaning and demand the plot.

The plot, of course, is complex. Full of diverse landscape, strange occupations and tenuous realities; a combination which lends to the feeling of space and time. Banks novels are shaped by plot over character; he explains that he ascribes more importance to ideas, leaving his characters to find their own niche, both in his science fiction and mainstream novels. Transition is no different.

On the subject of his women characters, Banks, who has been accused of misogyny, doesn't give much away regarding the development of two prominent women characters in Transition. There are plenty of noisy laughs and a few uncomfortable shuffles as Banks expounds on his choice of Christian terrorists in the novel, pointing out that the notions of original sin and limitless forgiveness lend themselves nicely to consequence-free bloodshed.

Referring again to Iain Banks and Iain M Banks during questions, Banks compares the job of an author with that of a carpenter; producing a chair one day and a table the next, but remaining the same person with the same set of skills.

Banks shines during questions; he becomes self-effacing, human; going off on tangents and enthusiastically talking with his audience, who reveal themselves to be sincere fans. They're the people who read Banks on the train and who have, as one audience member says, “been bed and bath partners for years”.