He didn’t know right away or he wouldn’t have co-written a book with him. But there’s no question that Terry Pratchett figured out who and what Neil Gaiman was by the time he wrote the Introduction to Good Omens, the book they wrote together. And I don’t think it’s an accident that despite the success of the first book, Pratchett never wrote another one with Gaiman in the 25 years that separated the 1990 publication of that book with Pratchett’s death in 2015.
Remember, Pratchett was a wordsmith, and a much better one than average. And since Gaiman’s reputation has always been one of being “a very nice, approachable guy”, Pratchett is clearly implying that he knows Gaiman is not, but is instead “an incredible actor”. Which events have subsquently confirmed to have been the case. Because that’s the only option that could “come as a surprise to many”.
