Samuel Pepys’s Diary (1660–1669) is an extraordinary document in many ways, but its most extraordinary aspect is that Pepys seems to have had no model for it. In terms of informality and naked self-revelation, it was unprecedented; the only comparable writings to precede it were Montaigne’s essays (1580–1588), but Montaigne wrote principally in the interests of philosophical inquiry, which Pepys did not—and in any case Pepys had not read Montaigne when he wrote the Diary. It is true that some of Pepys’s contemporaries kept journals, the best-known being John Evelyn’s, begun in the 1640s. But this was a decorous (not to say dull) chronicle of travel, politics, and public affairs, unlikely to shock anyone. Another of Pepys’s friends, the famous scientist Robert Hooke, also wrote a journal, but it was dry and relatively impersonal. So when the twenty-seven-year-old Pepys began his diary he ...