I might as well say that the book is (roll drums) The Passionate Witch, AKA I Married A Witch, by Thorne Smith (1892-1934), who has just gone out of Euro copyright. I've decided that a 1920s-30s comedy fantasy campaign based on Smith and possibly some others might be a fun idea - there's a bonus that this time setting makes it easy for referees to use CoC source material for backgrounds etc., although of course the mood will be VERY different. The books I want to include, but currently can't find my copies, are Topper and Topper Takes A Trip, possibly one or two others. I'd love to include as many as possible, so if anyone feels like taking a hand in this, and (for example) scanning one of the other books, I would be VERY grateful. The sole thing to note is that the source needs to be an edition pre 1980, since after that there may be editorial copyright in the work although the author's copyright has expired.
I'll put The Passionate Witch on line once I've finished with the corrections and HTML conversion; this will probably be after Easter unless I build up a LOT of speed.