“What really knocks me out is a book that, when you’re all done reading it, you wish the author that wrote it was a terrific friend of yours and you could call him up on the phone whenever you felt like it,” writes J. D. Salinger in The Catcher in the Rye. For 10 days every fall, that wish can come a little bit true at the world’s oldest literary festival, located in Gloucestershire, bordering the Cotswolds. For its 70th anniversary, the Cheltenham Festival hosts Debbie Harry and David Cameron (who both have books out), Max Porter, and many others. —J.V.