In his own variation on C. S. Lewis's trilemma of "Lunatic, Liar, or Lord," Ronald Knox writes: "I do not believe that, human nature being what it is, the immediate impression made by the preaching of the Gospel could have been so profound, if its first missionaries had only told to the world the story of a Man, clearly not mad, clearly not an Impostor, who was nevertheless prepared to accept the worship due to a God." The Gospel possesses a unique power to persuade its hearers to believe in Jesus Christ, to accept the friendship of the Son of Man whose Word is Truth itself. Differing from the continuous commentary-style of his other two Slow Motion books, Knox communicates the power of the Gospel in sermons brimming with his customary freshness, ingenuity, and anecdotal brilliance.

Culled by Knox himself from the extensive archives of his preaching over the years, the twenty-three sermons in The Gospel in Slow Motion offer a ready-bound retreat for religious and laity alike, for they are "Gospel" sermons in the fullest sense: their aim is the making of good Christians.