If you were to name the defining figures of the 21st-century conservative movement, Dennis Prager would surely rank near the top of the list. A longtime radio host and founder of digital educational platform PragerU, he is one of the world’s best-known public intellectuals, publishing more than a dozen books on religion, morality, and the foundations of Western civilization.

His latest book, “If There Is No God: The Battle Over Who Defines Good and Evil,” hits shelves next week. Drawn from a weekend-long lecture Prager delivered to 74 teenagers in 1992, it is a full-throated defense of objective, biblical morality at a time, he says, when more people dispute its existence than ever before. Though rooted in an earlier moment, the book holds new weight: In 2024, Prager suffered a catastrophic fall that paralyzed him from the waist down.

“A certain percentage of this book,” he reveals in the introduction, “was written by dictation and editing from my hospital bed. Were it not for Joel Alperson, who also organized and recorded the entire weekend, the book would not have been finished. We completed the book together. It is a testament to how important we both consider this work.”

Next week, our Abigail Shrier will interview Prager from his hospital room, so stay tuned for their full conversation. And below, we bring you an exclusive excerpt from his book, answering a question that many of us ask every day: In a world where profoundly evil things happen, how do we raise good people? —The Editors

Ever since I was very young, I have been preoccupied with one issue: Why do people hurt other people? Why do people do evil?

I was born in 1948, only three years after the Holocaust. I’m a third-generation American. Yet, when I was a kid, from the earliest time I could think, the Holocaust consumed me. When I was about 10, I watched a program on television, and I saw an image of Adolf Hitler. I asked my father, “Who is that man?” He said, “He was Hitler, and he killed six million Jews.”...