A Supposedly Fun Thing I'll Never Do Again, by David Foster Wallace, contains a journal type essay that he wrote at the US Open qualifiers, I think. He's a smart guy and loves tennis.
If you're really ambitious, Infinite Jest is also by Wallace and there's a lot about tennis in there, though in the form of fiction.
Motherless Brooklyn, by Jonathon Lethem. A guy so good that he makes you wonder if it's even worth writing. It's told in the first person and about a mafia hitman with tourette's syndrome. David Foster Wallace on lithium is what Lethem is. Hemingway to Foster's Faulkner.
The Physics of Star Trek. Using Star Trek as a reference point, a physics professor talks about science. Is beaming possible? What about warp drive? Find out in this book.
You've Gotta Be Kidding Me? Johnny Mac. Get some insight into the mind of an egotistical maniac. An excuse for every loss he's ever suffered. Good stuff though. Though he doesn't talk about his cocaine habit. Hehehe.
Tell you the truth, I'm still waiting for the tennis instructional book I totally love.