His letters are signed, save one, "Your affectionate uncle", yet Uncle Screwtape's purposes in writing to his young nephew are hardly innocent. Penned in a brisk, businesslike style, old Screwtape offers the gullible Tempter Wormword fiendishly clever advice on his most pressing concern: the winning of young lives to the devil.First published in 1941, The Screwtape Letters, a perennial best seller, has earned a place in the library of classics. The truths contained in C. S. Lewis's treatise on human nature are as old as the world, but his witty observations continue to confront and challenge believers and nonbelievers alike.The outcome of Screwtape's correspondence is not known. But judging from his final signoff -- "Your increasingly and ravenously affectionate uncle" -- his appetite for evil has not lessened.