"The Whole Christ: Legalism, Antinomianism, and Gospel Assurance—Why the Marrow Controversy Still Matters" by Sinclair B. Ferguson: Ferguson, a renowned Presbyterian theologian, explores the Marrow Controversy, a historical debate in the Scottish Presbyterian Church that had significant implications for understanding grace, law, and salvation. If you really want to understand the essence of salvation, this is the book you want to read. Outstanding!
"Discourses on God's Salvation of Sinners" by Stephen Charnock (eBook): Charnock, a Puritan divine, offers a detailed examination of the nature of salvation, with a focus on the grace of God in the salvation of sinners. His writings are a combination of deep theological reflection and practical application, with a strong emphasis on the role of Scripture.
"Redemption Accomplished and Applied" by John Murray: This book specifically focuses on the work of Christ in achieving salvation (redemption accomplished) and the work of the Holy Spirit in applying this salvation to believers (redemption applied). It's a concise yet thorough exploration of soteriological themes from a Reformed viewpoint. A classic.
"The Death of Death in the Death of Christ" by John Owen: Owen's work is a classic defense of the doctrine of limited atonement, arguing that Christ's death effectively achieved salvation for the elect. It's a more advanced text but invaluable for understanding this aspect of soteriology. Not light reading.
"Saved by Grace" by Herman Bavinck: Bavinck, a renowned Reformed theologian, provides a comprehensive and accessible discussion on the doctrine of grace, a critical element in Reformed soteriology. Bavinck is always very helpful.
"Putting Amazing Back into Grace" by Michael Horton: This book is a contemporary and accessible introduction to Reformed soteriology. Horton explains complex doctrines in a way that is engaging and understandable for modern readers.
"Saved by Grace" by Anthony A. Hoekema - Hoekema discusses the Reformed perspective on salvation, detailing how grace plays a fundamental role in the entire process of salvation, from election to glorification.
"The Cross of Christ" by John Stott - This book is a comprehensive exploration of the significance of the cross in Christian salvation. Stott examines the historical and theological aspects of the crucifixion, emphasizing its central role in redemption.
"Institutes of the Christian Religion" by John Calvin: This foundational work of Reformed theology includes a comprehensive treatment of soteriology. It's a classic text that has profoundly influenced Protestant theology. Calvin explores various aspects of soteriology, such as the fall of humanity, sin, the law, grace, faith, justification, and predestination. His treatment of these topics is thorough and deeply rooted in Scripture. Calvin's discussions on topics like election and predestination, the sovereignty of God in salvation, and the nature of faith and repentance are particularly influential and form a core part of Reformed understanding of salvation. I would recommend "Institutes of the Christian Religion" if you are interested in a deep, historical, and comprehensive study of Christian theology, including soteriology, from a Reformed perspective.