Pears: Fingerpost took quite a long time, although I had a good knowledge of the period through studying it as a student. Writing the book took about three years, and typically I would write in the morning and go to the library and do the research in the afternoon. The art-mysteries vary; as they are basically contemporary they need very much less research but occasionally a historical detail will take far longer to find out than it should—either because it is elusive, or because I find it intriguing and look into it for my own satisfaction. Writing them always takes longer than I think they will.

WAG: Graham Greene distinguished between novels and entertainments in describing his fictional works. Would you describe your own work in the same way?

Pears: I suppose that is the way they are beginning to come out. Many authors (especially crime writers) have done the same, but the convention tends to be to publish non-crime novels under a different name—even Agatha Christie, I think, tried her hand at love stories. Equally several more "literary" authors have published crime novels under a pseudonym as well.

WAG: A related question: Greene moved back and forth freely between his self-described novels and entertainments. Are you going to follow a similar pattern and offer something of An Instance of the Fingerpost's weight and ambition again in the future, perhaps between two Art History Mysteries?

Pears: That's the plan at the moment; I've just finished a crime novel and am in the middle of a weightier historical novel. I had thought that the crime one would be the last, but had what I think is a good idea for another one. If I ever get the next big one finished, then I will try and get it down, although that probably won't be for a year or so.

WAG: The big and philosophically ambitious 'historical mystery' genre has some famous contemporary examples, Umberto Eco's The Name of the Rose being perhaps the most prominent. Did you set out to write An Instance of the Fingerpost with such books in mind? Or did you find the manuscript growing in unexpected ways as you did your research and wrote the early drafts?

Pears: Certainly the manuscript grew all on its own—it began as a simple and straightforward historical crime novel, meant to be simply the first part. But then I decided to see if I could make it historically accurate, not merely a tale of contemporary people in fancy dress. That meant trying to fictionalise ways of thinking, as well as getting the material details right, and that posed problems of coping with the complex 17th century understanding of truth in a fashion which the final four-part story could illustrate fairly well. Eco comes in a little here, although in general the comparison with his (wonderful) book is not that helpful. In The Rose he quite knowingly plays the clever philosophical game of inserting a near-contemporary figure (Baskerville—Sherlock Holmes) into the medieval context. I decided to see if I could do without the conventional detective figure, and conventional means of gathering and assessing evidence, and still have something that would work as a mystery.

WAG: An Instance of the Fingerpost is set in 1663. Charles II has just regained the English throne, and experiment- and observation-driven science and empirical philosophy are gaining strength. It's a compelling period, and one thing that strikes me about it is how perfectly adapted it is to your plot. But I'm wondering which came first for you—the period or the plot? Did you choose the period setting because it fit the themes and plot lines you were interested in developing, or did you choose the period first and develop ways of matching your evolving plot and themes to it?

Pears: I think the two went together—the plot would be absurd set in almost any other period, and the 'periodisation' would be weakened if the plot (and its solution) had been more conventional. That said, it was the idea of using a different means of analysis to the clue-based deductive mode which led me to the period—I needed a large number of examples of ways of thinking to make it work, and this period is particularly rich in evidence through trials, scientific writings and so on.

WAG: An Instance of the Fingerpost includes a rather grimly detailed (if wryly amusing) autopsy that draws on both historically outmoded medicine (such as 'Will the heart of a poison victim truly not burn in a fire?') and contemporary anatomy. Indeed, throughout the book, you refer frequently to medical ideas of the 1600s. How much research in 17th century as well as 20th century medicine did you have to perform, to achieve that balance between historical and anatomical verisimilitude?

Pears: Quite a lot for the 17th century, as their understanding of illness was very different to our own, but all the terminology was different as well—for example, one major affliction for women was called "illness of the mother." This was a serious, sometimes fatal malady which has no descendant today. The medical details (how you die from blood-loss, for example) I checked out with doctor friends to try and get it right. The difficult part was to describe illnesses in ways which would be understood by contemporary readers in one way, but which could be explained in the book in a totally different, but equally logical fashion. The obvious example of this is probably the dream sequences, which have to be interpreted by readers in a Freudian sense, but which are just as reasonably and accurately interpreted in a pre-Freudian manner by the characters.

WAG: In addition to writing mysteries, you have also written extensively about art history, history, and finance. Which do you find is more comfortable to write in—fiction or nonfiction?

Pears: I like both—even the eurobond market has its interest, once you get into it and begin to understand how it works, although I doubt I will ever return to that sort of writing now. In some ways the subject isn't so important; it's the task of taking complex material and trying to make in comprehensible without simplifying which is the satisfying part, and that applies to eurobonds, the doings of the Vatican, art history and 17th century medicine equally.

WAG: Finally, two related questions. Many writers have a favorite 'neglected' writer—someone they think has been unfairly ignored by the general reading public. Do you have one yourself? And who do you think is the best under-appreciated writer working today?

Pears: My obscure authors keep on being discovered. I began reading the Patrick O'Brian naval stories years ago as well as Robertson Davies, but neither of these can be called unrecognised any more. I even gave a Harry Potter to a Godchild before he made Madonna seem like an unknown. Delightful for the authors, and well-deserved, of course—but I always feel ever so slightly betrayed when one of my private joys becomes public property like that...