Any new book by C. S. Lewis (The Screwtape Letters) is bound to receive an eager and curious welcome, eager because he seems to know so surely the state we are in at the moment, a state easier to bear because of the shafts of light his agile mind throws upon it to reveal its real dimensions, and curious because we can never know the direction from which the light may come. This his latest book fully upholds this reputation. It is comprised of a series of essays. He is concerned with the efficacy of prayer, and is able to communicate to the reader a sense of what real prayer is that does not avoid the difficulties he encounters. "Refinement", "religion" and "culture" come off rather badly as they are commonly understood. He comes out on the side of "good work" as against "good works", and a sound religion that is not shaken by rocketry. The "World's Last Night", from which the book derives its title, is a moving and urgent plea to live as if the present were the world's last night, -- and finally, as if anticipating his readers' demand for an encore, a chapter entitled "Screwtape Proposes a Toast". Here, with unholy delight, we read the advice of a very experienced devil given at the annual dinner of the Tempters' Training College for Young Devils. Our current personal and corporate sins get the full treatment, and we shudder in applause.