The historian, whose new book is the Rose Pastor Stokes biography “Rebel Cinderella,” treasures his first-edition copy of “The Jungle,” by Upton Sinclair: “This one gave us our pure food and drug laws.”

What’s the last great book you read?

Joseph Roth’s “The Radetzky March,” for the second time. Such a multilayered portrait of the vast, creaky, fragile Austro-Hungarian Empire on the eve of collapse. All those ethnic and class tensions simmering under the surface while shiny-booted hussars parade through sunlit streets.

Are there any classics that you only recently read for the first time?

Kafka’s “The Trial.” He fully foresaw Stalin’s show trials 20 years before they happened. Somehow he sensed the potential for such madness in the war-crazed Europe of 1914 and 1915 — and in the life of his tyrannical, guilt-inducing father.

What’s your favorite book no one else has heard of?

“The Gypsies,” by Jan Yoors. As a 12-year-old boy in Europe in the early 1930s, he ran away with a band of Gypsies, lived with them on and off for 10 years, and, decades later, wrote this luminous memoir.

What book should everybody read before the age of 21?

“The Adventures of Huckleberry Finn,” for its sense of justice as something deeper than the law. Although Huck believes he’ll be doomed to hell for doing so, he still decides to help Jim, Miss Watson’s lawful property, escape from slavery. I tear up when reading that part aloud to my grandchildren.

Whom do you consider the best writers (novelists, essayists, biographers, journalists, poets) working today?

Ben Fountain’s novel, “Billy Lynn’s Long Halftime Walk,” dazzled me with its evocation of the madness of the Iraq war, all seen through the prism of the halftime show at a Dallas Cowboys game. I’ll read anything he writes. One of the few nonfiction writers I’d say that about is Katherine Boo.

Which books by contemporary historians — both academic and amateur — do you most admire?

Two historians in the academy who write splendidly are Jill Lepore and Simon Schama. But since I never went to graduate school, I also appreciate others who practice history without a license. Richard M. Watt, author of an excellent book on the French Army mutinies of World War I, was a construction company executive. The peerless Barbara Tuchman had no advanced degree or university post. And the former book and newspaper editor Claire Tomalin is the finest historical and literary biographer alive.

What do you read when you’re working on a book? And what kind of reading do you avoid while writing?

Since I mostly write history, I have to wade through a lot of raw material. Currently that includes informers’ reports to the Bureau of Investigation (predecessor of the F.B.I.) during the Red Scare of 1917-20. I also have to read a lot of scholarly monographs. Since the prose of neither undercover agents nor academics has much sparkle or suspense, when I’ve finished work for the day I’m hungry for something that picks me up and carries me along, like one of Ben Macintyre’s real-life World War II or Cold War spy tales.

What’s the most interesting thing you learned from a book recently?

In the harsh crackdown on dissent kicked off by American entry into World War I, some 75 newspapers and magazines had entire issues banned or were shut down completely. And this sweeping censorship continued for more than two years after the war ended. Imagine which later president would relish just such powers.

Which genres do you especially enjoy reading? And which do you avoid?

I admire novelists who can build a whole world and keep me in it for several books. My favorites: Paul Scott’s magnificent Raj Quartet on the last days of British India; Pat Barker’s trilogy on World War I; Doris Lessing’s Martha Quest quintet. Elena Ferrante’s four Neapolitan novels may also rank with these; I need to let them sit a little more since finishing them to be sure.

A superb nonfiction trilogy is Patrick Leigh Fermor’s stunning account of walking from Holland to Istanbul in 1933. A zestful 18-year-old’s experience told, thanks in part to his lifelong writing block, with the dazzling style of a far older man. The last volume was still unfinished when he died in his 90s.

How do you organize your books?

Fiction, nonfiction and then sections for the various subjects I’ve written about. Plus a vast “To Read” set of shelves where some volumes, alas, have sat waiting for decades.

What book might people be surprised to find on your shelves?

I was an antiwar activist in the 1960s, and have written, in parts of two books, about the brave pacifists of 1914-18. But my shelves hold many volumes of military history, and of Patrick O’Brian’s Napoleonic War maritime novels. And every single volume of stories by John Updike. I have mixed feelings about his novels, but he was our finest writer of short stories since Hemingway. I can easily forgive him for being a Vietnam War hawk.

What’s the best book you’ve ever received as a gift?

A first edition of Upton Sinclair’s “The Jungle.” Who says books can’t change the world? This one gave us our pure food and drug laws.

Who is your favorite fictional hero or heroine? Your favorite antihero or villain?

I’ll let others pick the good folks; I enjoy villains more. Take, for instance, Robert Moses of “The Power Broker,” the devastating biography by Robert Caro. Perhaps you have to be a native New Yorker like me to read all 1,344 pages of this searing demolition job on the man who laced a great city with ugly expressways and had nothing but contempt for people too poor to own a car. But the book is an extraordinary achievement that should shame the hundreds of reporters and editorial writers who naïvely glorified Moses over the decades.

What kind of reader were you as a child? Which childhood books and authors stick with you most?

My favorites were the “Freddy the Pig” series of Walter R. Brooks. Heroic detective, pilot, poet, magician and victor over all bullies and humbugs, animal or human, Freddy remains a model to us all. And in his First Animal Republic it was one animal, one vote — a great improvement over our Electoral College.

How have your reading tastes changed over time?

Not enough, perhaps. Although I have moved on from Freddy the Pig.

What book would you recommend for America’s current political moment?

Trollope’s “The Way We Live Now,” the story of a financial con man who goes into politics.

You’re organizing a literary dinner party. Which three writers, dead or alive, do you invite?

E. L. Doctorow, a friend and mentor whose encouragement early in my writing life meant more than he could have imagined. George Orwell, to make sense of an era that seems to be following the script of “1984.” And Ryszard Kapuscinski, who specialized in writing about demagogues even before we had a world awash in them.

Whom would you want to write your life story?

I already wrote much of it in “Half the Way Home: A Memoir of Father and Son.”