The index, by giving it one line, mimics the biography’s own restraint. Kanigel knows we want the romantic tragedy—the dying mathematician shipping formulas home. The index refuses to overindex the miracle. It trusts you to find it.

But then look closer.

Notice the subhead under : “appreciation of Ramanujan’s genius,” “collaboration,” “ lectures on Ramanujan .” Yet Hardy gets something Ramanujan does not: an entire sub-section titled “personality of.” Kanigel’s index quietly confesses what the narrative itself wrestles with—this is a dual biography. The index lists Hardy almost as fully as it lists Ramanujan, because you cannot index one without indexing the other. The symmetry is subtle but damning: the white, Cambridge don gets a psychological profile; the Indian clerk gets a list of illnesses and notebooks.