Jason Webster, who's lived in Spain since 1993, introduces Chief Insp. Max Cámara in Or the Bull Kills You.

You've written a number of nonfiction books about Spain. Why the switch to fiction?

I aim to be a storyteller first and foremost, and so for me the differences between fiction and nonfiction are quite minor. Character, dialogue, an overriding theme, pace, narrative—these are all there in my nonfiction books. Writing novels was a natural progression, which frees me up to experiment with different points of view and ways of seeing the world. I wanted to write a crime novel where a bullfight-hating policeman has to investigate the murder of a matador. Something about that tension drew me in—the victim is little better than a murderer himself in the eyes of Chief Insp. Max Cámara.

What's the biggest stereotype commonly held about bullfighting?

That it's very macho. There is an element of that, of course, but the sexual symbolism of the bullfight is more complex. Man and bull are swapping gender roles throughout the fight, so the matador represents both male and female, which is why you never see a bearded bullfighter.

Is bullfighting still popular today?

Five or six years ago bullfighting was on the wane. Ticket sales were down, and people were wondering if it would survive. Then a bullfighter called José Tomás came out of early retirement and reignited it with his classical, very pure style, putting his life on the line every time he stepped into the ring. Since then, Catalonia has banned bullfighting, while other regions, such as Madrid and Valencia, have declared it a “cultural heritage asset,” giving it some kind of legal protection. If anything, the Catalan ban has probably made it more popular in other areas of Spain. It's not considered a sport, by the way—it's a drama. The bullfight reviews are next to the ballet and opera reports in the newspapers.

Where did the idea of plotting your books on index cards laid out on a carpet come from?

I was having difficulties with the second book in the series, and so wrote out plot points on cards. Then I moved away from my desk and started scattering them on the floor, hoping to find a pattern. It was only then that I realized that the carpet they were lying on could help me structure the story, with its horizontal lines (it's a Moroccan Berber rug). So it forms a grid-pattern, with the stripes giving me chronology, and the various plot lines working vertically down the length of the carpet. That way I can easily see how they interact (thanks to the horizontal stripes) and get the timings right.