Charles Williams is in many ways a paradox: a working-class man who lectured on John Milton at Oxford University; a devoted Christian whose novels explore blasphemies and black magic; an eloquent philosopher of human and divine love whose own romantic life was often deeply troubled. Like those of his friend C. S. Lewis, Williams's talents were evident in several genres: not only poetry and fiction but also plays and various nonfiction, including biography, poetic theory, theology, literary essays, and book reviews. He also left his mark as an editor for Oxford University Press and as a member of the Inklings, a writers' group that included Lewis and J. R. R. Tolkien.

Perhaps most readers know Williams through his seven novels. Critics have praised Williams's novels for their ability to portray spiritual truths, condemned them for their sensationalism, analyzed the precision and delicacy with which Williams writes, and complained...