You introduced willpower as a new stat in Beneath Nightmare Castle. What made you tinker with the rules in your first book?
I think – and I must stress just how long ago all this occurred, and that my memory is notoriously poor in the absence of documentary evidence – that I had felt from the inception of Fighting Fantasy books that the standard stats made for a rather simplistic game experience. In each of my books I tried to stretch the original Fighting Fantasy concept, but in each case in a way that I hoped was appropriate to the subject matter. In a tale of Lovecraftian horror, willpower seemed like the necessary additional ingredient.