The third of Ian Sansom's Mobile Library Mysteries is
The Book Stops Here (Harper, 2008). Like the first two, the mystery itself is only a small (and not entirely meaty) part of the book, most of which is focused on Sansom's brand of semi-snarky humor and satire. He seems to be working on adding a little more depth to his characters here, particularly the narrator (that'd be Israel Armstrong, the portly, pathetic librarian) and his sidekick (the gruff van-driver Ted Carson).
As with the other volumes, a good light read, with some very funny moments. My favorite bits were the few moments where Armstrong actually discusses the normal day-to-day operations of the mobile library; I laughed out loud through those pages.