TO MILLIONS of 21st-century readers and moviegoers, especially adolescents, C.S. Lewis (1898-1963) might be best known as the creator of the Narnia books, which supplement their collections of Harry Potter and Lord of the Rings volumes. Older adults may remember him for The Screwtape Letters, in which Screwtape, an experienced devil, explains to Wormwood, his nephew and a novice tempter, how best to ensnare his assigned human target.

Even at the age of 70, this novel continues to sell well, thanks in part to a new theatrical version that has played off-Broadway for more than 300 performances, in Chicago (six months) and in Washington, D.C. (10 sold-out weeks). A two-person play with a single speaking role, The Screwtape Letters challenges audiences to look not only outward to the stage but also inward at themselves.

The script “pulls back the veil of the spiritual world that most of us inherently know is there,” says Max McLean, who plays Screwtape as a dapper raptor with a grand goatee, brocade smoking jacket and matching vest, his eyes avidly searching for fresh carrion. “We tend to suppress that world because it’s too powerful, too much to handle,” he told St. Anthony Messenger recently.