_Myth-Ing Persons_ by Robert Asprin
I think I read one (or more) of the MythAdventures books when I was a kid -- he started writing them in 1978, so that sounds about right. I don't remember which one(s), but I had a vague memory that I liked it at the time, so when I had a hole in my reading schedule and saw it on a shelf, I grabbed it on the way out the door.
It's ... fine. Somewhat entertaining, some amusing parts, I like the characters. Not a lot of what you might call "content," though. Well, the book isn't very long (according to Amazon, the mass-market paperback is 208 pages -- if that's true, that must be some *big*-ass type), so I guess there's only so much that's going to happen.
I enjoyed it, overall. I'm not going to run out and try to find the rest of the series, but I might recommend it to Sarah when she's got a space in *her* reading schedule and is looking for something light and unassuming.