Pegasus Books is publishing British author Donald Thomas’s fourth collection of new Sherlock Holmes stories, Sherlock Holmes and the King’s Evil.

How did you come to write your first pastiche?

The major influence was my father, who would read aloud the omnibus edition of the Holmes stories when I was a child and then would start over again at the beginning. I remember thinking at the time, wouldn’t it be a good idea if there were more stories for him to read. I didn’t actually start thinking about writing them until the 1990s. I had been rereading the originals, and I thought, this man was such an asset to the country, why was he not employed on more official business? And wouldn’t it be a nice idea to put Holmes into some of the real cases from his time and see how he would get on with solving them?

What were the biggest challenges in creating new problems for Holmes to solve?

To be faithful to the original characters and the general world of Conan Doyle, and not to put anything in that would be fashionable nowadays. With Holmes, you’ve got to be very careful not to make him something he wasn’t. The second priority is to extend the character somewhat, so that you’re giving the reader something new.

How did you go about doing that?

I’ve done it by working in some new friendships for him. One is with Adm. Jackie Fisher, the creator of the modern royal navy, the sort of man Holmes would like because Fisher’s view of war was completely unorthodox. The second is Sir Marshall Hall, one of the Great Defenders; he was almost unbeatable in court. I thought that he and Holmes might work on a few cases, where someone who seemed to be the obvious suspect was in the dock until they intervened.

Have your stories ever surprised you?

I’ve sometimes found myself with an ending that I wasn’t expecting. I’m currently working on another book of pastiches, and the first story has Holmes investigating the circumstances in Henry James’s The Turn of the Screw. I thought I knew how it was going to turn out, but I ended up with quite a different ending. I don’t think it’s necessarily important to surprise readers, if at the end they feel they’ve read a gripping story. Sometimes the ending can be seen a long way off. The first story in Sherlock Holmes and the King’s Evil is based on an Oscar Wilde story, and I wouldn’t be surprised if some correctly anticipate the ending.