Undoubtedly the lesser-known of the five, is Holiness by J. C. Ryle. Here we recommend Faithfulness & Holiness: The Witness of J. C. Ryle, An Appreciation by J. I. Packer (Crossway, 2002), which is comprised of both the original edition of Holiness coupled with a terrific survey of Ryle’s life and work by Dr. Packer.