Originally published in 1781 in two volumes, Cardiphonia is now a standard textbook for many Bible students considering pastoral ministry. The first 26 letters were addressed to Lord Dartmouth, who recommended the author, John Newton, for the parish at Olney where he served for over 40 years. Newton wrote many ecclesiastical books, sermons, letters, and hymns during his time at Olney, including the hymn for which he is most famous, “Amazing Grace.”