In this focused and enlightening treatise, John Owen defends the truth and coherency of the doctrine of the Trinity. Owen responds most explicitly to the heresy of “Socinianism.” Socinianism holds that Christ did not pre-exist before being a man. Working with both Scripture and tradition, Owen vigorously argues for a traditional account of the Trinity. Owen doesn’t just defend this doctrine, however; he also calls for faith in it as well. To indicate the importance of the Trinity, Owen ends his treatise with an explanation of the satisfaction of Christ. For without the Trinity, Owen argues, there can be no doctrine of satisfaction of sins through Christ.