Authentic Christianity, Volume 1 is a collection of expository sermons preached at Westminster Chapel, London by David Martyn Lloyd-Jones — known to his congregation simply as "the Doctor." Working through the first three chapters of Acts, Lloyd-Jones holds the early church up as a mirror to the modern church and the modern soul. His central argument: Christianity is not an ethical system, a social program, or a religious sentiment — it is a supernatural intervention by the living God, beginning at Pentecost and continuing wherever the Holy Spirit works regeneration. The book is organized around three passages: Acts 1–2 (Pentecost and Peter's sermon), Acts 2:41–47 (the four marks of the early church), and Acts 3 (the healing of the lame man and Peter's second sermon). Lloyd-Jones engages throughout with liberal theology, nominalism, and every effort to reduce Christianity to a creed-free "way of life." The preaching is vintage Lloyd-Jones — doctrinal, searching, and urgent — pressing every listener to examine whether their Christianity is authentic.