I believe most, if not all, the letters between Fitzgerald and Hemingway are in this volume. So are letters by them to others (i.e. Max Perkins) where Scott will discuss Ernest or vice versa. Bruccoli uses these as a means of evidence in showing the complicated relationship between the two, and what they thought of each other's works. Some photos also. The reader needs to have more than a passing interest in these two authors. As I do 👍