The starting point for Heredity was Jonathan Wild – what was it that drew you to him? You've spoken about the moral ambiguities in what he was doing – were you making a comparison with the scientific world, and assisted reproduction, in Heredity?

It really wasn't that explicit–in fact, that connection remained pretty fuzzy in earlier versions of the novel. I'd say this is a more psychological interest, not so much a philosophical or political one. Jonathan Wild is one in a long line of characters I've been drawn to over the years, men in history or literature who have been widely vilified but who strike me as having had a more complex or interesting relationship with their own wrongdoing than is widely acknowledged. Shakespeare writes his villains like this–Iago is the most famous example–but you get them in life as well. I feel a strong kinship here with a writer who's superficially completely different from me, Gitta Sereny, who has spent much of her career wrestling with exactly this problem. Her biography of Albert Speer wonderfully tackles the question of how Speer understood his own actions, and if you juxtapose this work to her book-length studies of Mary Bell (who murdered a small child when she was just a child herself) you start seeing a distinctive set of interests that I very much share. Once you look inside any so-called sociopath, don't you see an impossible mixture of rationalization and self-justification and remorse and self-aggrandizement? This is what I find so interesting about Jonathan Wild.

You write your own blog. What do you think of the explosion of literary related blogs in recent years? There are a number of authors, who have their own blogs, which by their nature reveal a certain amount. Do you ever get the sense that it might detract from the fiction? In the past authors were more reclusive, by necessity, and it added a certain mystique, I would argue.

I love lit blogs. First and foremost, since I've started reading them, the quality of my casual reading has gone way, way up. Instead of relying on whatever used paperbacks I pick up from the guy selling them on the street, plus what's caught my eye in the New York Times Book Review or the Guardian Books section, I can get great recommendations from people reading really deeply in particular genres and so on. But I like to see behind the scenes, as it were. I know other people who share your belief in the importance of mystique and privacy. But I read Neil Gaiman's blog avidly–his is an excellent example of the mix an author might aim for, updating fans on new projects, telling anecdotes about family life, pointing people to interesting articles or good causes–and it makes me more, not less likely to buy his new book the minute it hits the shelves. That said, a quick look at my own blog will show you that while I write a lot about what I read and what I think of it, I am relatively unforthcoming about anything to do with my actual life, including my work life. I have a strong sense of privacy and am always very conscious that anything I post may be read, for instance, by lots of my students.

You've said, on your blog, that your rule for novel reading is to go from the most 'trashy' to the least. What do you mean by 'trashy'? What are the qualities you admire in a 'trashy' novel, and who are the writers who best capture those qualities?

It's funny how hard it is to come up with an adequate vocabulary for talking about these things. Trashy… hmm… I think it will be clear to anyone what this means in practice. If I come home with two novels, and one of them is David Mitchell's Cloud Atlas and the other is Terry Pratchett's Going Postal, it's one-hundred-percent-certain that I'm going to read the Pratchett novel first. (I always think that everyone must share this tendency of mine, but I seem to be wrong about this. Many people will read the more obviously worthy and challenging novel before the immediately gratifying one.) Other ways of describing ‘trashy’ novels: page-turners; books you can read on a train. (If the book you have on a train isn't trashy enough, you end up staring out of the window instead of reading, and it's very boring.) The qualities I admire in a ‘trashy’ novel are basically those of the best commercial fiction: appealing characters first and foremost, interesting ideas, clear and attractive style, the longer the better. Genre writing often fits the ‘trashy’ bill, but so does certain classic fiction. Jane Austen and Charles Dickens are trashy, and so is Trollope; George Eliot and Henry James are admirable but not at all trashy (though Felix Holt the Radical is certainly Eliot's trashiest book). I love many different kinds of novels, but there are certain trashy novels that I love more than anything in the world: in adolescence, for instance, these prominently included the novels of Dick Francis, Mary Stewart, Joan Aiken and Georgette Heyer. I have read Robin McKinley's Sunshine about five times already, and it only came out last year. I love that book. It's not trashy in any real sense–it's extremely well-written and smart–but it is completely addictive.