"F" takes Kinsey Millhone out of town to solve a 17-year-old murder case, and she's soon up to her ears in decades-old clues and crimes. One of the things Grafton does best is to create vivid and realistic communities of people. "F" is a great example of this--each character we meet is interesting, complex, AND has interactive relationships with other characters we've met. Everyone's connected, and when Kinsey solves the mystery, it makes sense because it FITS the characters.
My only (minor) complaints are that I missed the usual cast of characters (especially that Hungarian-type woman at the bar where Kinsey eats) and that Grafton indulges in a little moralizing at the end, which seemed heavy-handed.