Christopher Hitchens’s introduction to George Orwell’s “Diaries,” among the last things he wrote before his death, is meant as a tribute to one of the writers he most admired, but it can also be taken as a warning. “Read with care, these diaries . . . can greatly enrich our understanding of how Orwell transmitted the raw material of everyday experience into some of his best-known novels and polemics.” Read with care? What is Hitchens trying to tell us with that phrase? A few sentences later we have: “This diary is not by any means a ‘straight’ guide or a trove of clues and cross-references.” About the creative process that went into constructing one of the novels, Hitchens says Orwell “gives us little or no insight.” Most tellingly, he refers to the entries as “meticulous and occasionally laborious jottings.” Read with care, Hitchens’s introduction alerts Orwell devotees that they should not expect the same pleasures from this book that they get from other of his writings.

This collection contains all 11 of the diaries available to us, along with entries from two of Orwell’s notebooks. Additional diaries may exist. Peter Davison, who has scrupulously prepared these documents and was the lead editor of Orwell’s 20-­volume “Complete Works,” says that “it is as certain as things can be that a 12th, and possibly a 13th diary” — seized by authorities during the Spanish Civil War — “are secreted away in the N.K.V.D. Archive in Moscow.” Orwell may also have kept a journal at the start of his professional life in the 1920s, when he was an imperial official in Burma, but that is almost certainly lost....