James Henley Thornwell (1812-1862) employed John Calvin's Institutes of the Christian Religion as his textbook at Columbia Theological Seminary because, as Bruce Gordon notes, he "regarded Calvin's book as the fullest expression of Reformed theology" (John Calvin's 'Institutes of the Christian Religion': A Biography, p. 117).
Benjamin Morgan Palmer recounts remarks by a student concerning Thornwell's opening lecture on the Institutes: "I remember well the account he gave of his visit to Calvin's grave, and of his musings upon the molding influence of the mighty Reformer upon theological thought: and the statement of his conviction, that the emergencies of the conflict with Rationalistic infidelity were now forcing the whole Church more and more to occupy Calvin's ground. His pale face alternated with flushes of red and white, as he was speaking, and his eye dilated until it seemed almost supernaturally large and luminous. Deeply moved myself, and fired with an enthusiasm for Calvin, which I hope never to lose, I turned a moment's glance to find the class spell-bound by the burst of eloquence and feeling" (The Life and Letters of James Henley Thornwell, p. 534). Gordon comments: "Thornwell must have divined some secret knowledge to have known where Calvin was buried" (Ibid., p. 118).
There are modern study guides to Calvin's Institutes, such as J. Mark Beach, Piety's Wisdom: A Summary of Calvin's Institutes with Study Questions (2010), but what we find in Thornwell's Collected Writings, Vol. 1, in Appendices C and D, starting at p. 597, although incomplete, constitutes a valuable 19th contribution to the study of Calvin's magnum opus.
Titled "Analysis of Calvin's Institutes, With Notes and Comments" and "Questions on Calvin's Institutes," the former is a summary and analysis of the first three books of the Institutes, while the latter is drawn from the first book. One wishes that we had more of Thornwell's insightful comments and study questions on the rest of the book, but what we have here is a treasure. His analysis is skillful, and his questions are probing, both intended to elucidate a deeper understanding of Calvin's teaching.
If you are seeking a guide to this world-changing book, consider Thornwell's 19th century contribution to studies of the Institutes.