Psmith is generally regarded as Wodehouse's first great comic creation and here, liberated from the school context, he comes into his own. The account of his haunting of Bickersdyke at the Senior Conservative club is the funniest passage Wodehouse had written up to then.
This is still an early novel, far from the later glories of Blandings Castle and Jeeves, but if you're a fan and have somehow overlooked this one it's highly recommended.