Introducing... Author Alan Campbell

'SUSPENDED by chains over a seemingly bottomless abyss, the ancient city of Deepgate is home to a young angel called Dill, an assassin named Rachel and a psychotic murderer hungry for revenge – or redemption. But soon a shocking betrayal will unite all three in a desperate quest . . ."

So began Scar Night, the first installment of Edinburgh-based sci-fi writer Alan Campbell's Deepgate trilogy, the second volume of which, Iron Angel, is launched at Waterstone's this evening, where the author will be on hand to read from the new adventure and sign copies.

Exploring Campbell's past, you might be forgiven for assuming the vivid imagery the 36-year-old conjures up is a result of the years he spent working in the computer games industry developing, among others, the ground-breaking Grand Theft Auto series. But you'd be wrong.

"I've always been very interested in photography and have sold pictures to various newspapers and magazines, so that's where the imagery comes from really. From my love of photography and art," explains the Falkirk-born writer, who graduated in computer science at Edinburgh University before, initially pursing a career in the games world.

He recalls, "As a kid I enjoyed playing computer games and the plan was to get a job writing them. So, after university I got a job with DMA Design, the company that made Lemmings. I found myself in a brand new team working on a game that, three years later, turned out to be Grand Theft Auto – it was originally meant to be a dinosaur game."

A year travelling followed, after which Campbell found himself back in Edinburgh working at Rockstar on the 3D version of Grand Theft Auto, by the end of which he admits he'd "had enough of doing the same thing over and over again."

Instead, he decided to turn his hand to writing and to develop an idea he had first dreamed up many years before.

"After graduating, I worked in a telephone exchange in Bathgate where I saved up for a year to go inter-railing," he reveals. "I ended up in Budapest without a penny, and got a job working in a Youth Hostel. As I didn't have a TV I filled my time writing – the idea just popped into my head one day. I wrote three pages and forgot about them for the next ten years."

Those pages provided the basis of Scar Night, which was never intended to be the first of a three- book series.

"I wrote Scar Night without any further story in mind, but when the book sold here and in the US, the deal I was offered was a three-book deal. I was pleased, but it did mean that there was a bit of pressure on me to come up with a continuation of the story, which was difficult," he says.

That continuation has been described as a "stunning follow-up". After a destructive battle, the ancient swaying city of Deepgate has been overtaken. Most of the chains that suspend it have given way, toxic fumes are emanating from blazing structures and the temple once inhabited by the ruling Presbyter now dangles upside down above the once-uncharted abyss.

The victorious Spine have imposed martial law and are ruthlessly pursuing all who attempt to leave. Amid the turmoil two captives return – Dill, now toughened by war, and Rachel Hael. Scar Night may have introduced Dill and Rachel but Iron Angel cements them as the central figures in Campbell's imaginary world.

Meet them and their creator at Waterstone's tonight.

• Alan Campbell, Waterstone's (West End), Princes Street, tonight, 6pm, free, 0131-226 2666