I know, you're asking ... who?
Melrose Plant is a recurring character in Martha Grimes' books. He's the 'sidekick' to Richard Jury, the detective.
I love Melrose Plant. Seriously. I think he's one of the most interesting secondary characters I've ever read. Although her plots are getting a bit trite (I mean, how many times can Plant go undercover and fake out suspects?) he still remains true to his character. Jury has deviated a few times (Grimes' awkwardness with sex in her books is legendary and the way she tosses Jury into bed is almost comical), but Plant is still intriguing and has more depth than Jury. Plus his awkwardness around children, his affection for his dog, Mindy, and his tussles with his aunt Agatha are great.
I still remember one scene in Jerusalem Inn where Plant is in the back seat of the car, trying to peek into the Christmas packages. Or the scene in Help the Poor Struggler where he and Brian are in the pub and Plant puts money on the table to pay for Brian kicking in the jukebox. MP has just a fine sense of what's important in the world ...
Of course, it helps that he's rich, has given up his titles (for reasons we suspect but have never been outright told), knows all about fine wines & cars, and has a huge estate in England in Long Piddleton where he hangs out at the Jack and Hammer with equally intriging people (Joanna the Mad, Vivian, Diane, Marshall Trueblood).
It's because of Grimes I became a mystery writer and because of her I try to find characters who are as interesting, well-rounded, and unusual. If I ever do a series, I want people like Melrose Plant in my books. You never know what they'll reveal next.