In a life that was relatively brief but exceedingly active, George Orwell was, among other things, a police officer in Burma, a dishwasher in France, a tramp in England, a combatant in Spain, a war correspondent in Germany and a farmer in the Hebrides. Like many people of his era — he was born in 1903 and died in 1950 — he was also a prolific letter writer, and a particularly captivating and thoughtful one at that, thanks partly to the wealth of experience he had acquired.

“George Orwell: A Life in Letters” is a judiciously chosen selection of some of the most interesting of these casual writings, from a 20-year period that included both the Great Depression and World War II. Peter Davison, who selected and annotated the letters, was also the lead editor of Orwell’s 20-volume “Complete Works” and has sought here to distill Orwell’s essence, as man and thinker, into a more manageable size and format.

The letters are appearing a year after the publication of Orwell’s diaries, which focused on the concrete and often mundane details of his daily life, including the number of eggs laid by his hens. This book has a bit of that, too, but more frequently serves as a platform for Orwell to expound on weightier topics, often in terms that still resonate today....