It is the worst-selling of my books (by a fair bit), but the people who like it seem to REALLY like it, which is cool. Also, the current cover (designed by nerdfighter Sarah Turbin) seems to have given the book fresh life, so it may be too soon to judge.
There’s a lot at play here. I do think the fact that the book involves a lot of abstract mathematics (even though you don’t have to know anything about math to read the story) is intimidating to some people. Also, Colin isn’t a very easy person to like, especially at first. And I think for some readers the book feels more like an exercise in cleverness or somehow less emotionally grounded than my other books. (My favorite professor from college, who God bless him cannot tell a lie, said, “I liked your first book. Your second one, schticky.”)
All that noted, Katherines has still had a great life, and I’m really pleased that so many people have responded to it so generously over the years.