I read this book -- well, twenty years ago! I wasn't a very experienced developer at that point, and I found the book extremely helpful. What I've never been

I read this book -- well, twenty years ago! I wasn't a very experienced developer at that point, and I found the book extremely helpful. What I've never been able to figure out is why it has never been updated in all that time. Does anyone know? I heard from someone who heard from someone that there was some kind of legal reason they couldn't update it, but I can't really imagine what that would be. Obviously, lots of books don't go into multiple editions, but given what this one was about, I felt like it couldn't possibly be entirely full of "timeless advice" that wouldn't ever show its age.