When [Graham] Greene died, his heirs and trustees were faced with the conundrum of what to do about his library, an archive of some 3,000 volumes. This was not just a matter of dispersing several boxes of hardbacks. Greene’s personal collection deserved to be kept intact as almost a primary source, for one very good reason: Greene used to annotate his books with all kinds of marginalia, reflecting a long and crowded life of writing, politics, travel and friendship.

Scattered along the margins, and jotted on the flyleaves and endpapers of his books are thousands of tiny, meticulous, handwritten notes and comments: skeletal plot summaries; word counts for the novel-in-progress; fragments of stories, films and plays; and snippets of dialogue, many of them made in the course of Greene’s constant wandering. These add up to a quite singular imaginative phenomenon, a window on the mind and fancy of a major 20th century writer, often at the very instant of inspiration.