Edward Fisher's "The Marrow of Modern Divinity" is written as a dialogue that draws upon the insights of Martin Luther, John Calvin, and other notable 16th and 17th century Protestants to distinguish the law from the gospel and to confront the errors of antinomianism and legalism. While these issues are of perennial relevance for Christ's church, the antiquity, intricacy, and format of Fisher's book can make it daunting for contemporary readers. In this simplified version, most of Fisher's material has been retained, the best insights from Thomas Boston's 18th century annotations have been incorporated directly into the dialogue, and the content has been revised and edited to make it more accessible for today's readers. This second, expanded edition contains an entirely new section (Part 4) that contains a simplified version of the material that Fisher published in 1649 as the second part of "The Marrow." Andy Wilson is the pastor of Grace Presbyterian Church (OPC) in Laconia, New Hampshire. His writings have appeared in Modern Reformation magazine, Ordained Servant journal, and online at the Aquila Report.