The book takes the form of a letter to Hadrian's adoptive grandson and eventual successor "Mark" (Marcus Aurelius).

The emperor meditates on military triumphs, love of poetry and music, philosophy, and his passion for his lover Antinous, all in a manner similar to Gustave Flaubert's "melancholy of the antique world."

The notion of writing the book from the point of view of a dying Hadrian occurred to her after reading a sentence in a draft from 1937 stating: "I begin to discern the profile of my death.

He also talks of his early interest in astrology and his lifelong passion for the arts, culture, and philosophy of Greece; themes which he revisits throughout the book.

Hadrian, who is around thirty years old at the end of the war, describes his successes in the army and his relationship with Trajan who is initially cold towards him.

Hadrian begins reflecting upon his advancing age and his change in temperament, recalling one incident where he accidentally blinds his secretary out of rage.

During an important siege, he despairs over the unraveling of his plans for peace, his ailing heart condition, and later over the rampant destruction in Judea.

Nature fails us, fortune changes, a god beholds all things from on high…"[9] During his final years in Rome and at his villa in Tibur, he ponders his succession and his thoughts turn to a memory of Marcus Aurelius as a virtuous and kind-hearted boy.