Lois Weisberg, Chicago’s celebrated cultural commissioner, has two writers for sons, Jacob and Joseph. In January, they both publish books. Sibling rivalry, or simply good genes? Chicago called each up to ask.

JACOB WEISBERG

CV: Editor of Slate magazine, 43, married, with two children. Lives in Manhattan.

New title: The Bush Tragedy (Random House), which asks why George W. Bush failed as president

Jacob says: “My argument is that he tried to make himself the polar opposite of his father, both in terms of decision making but also his views on policy, especially Iraq.”

Joseph says: “I loved it. In the middle, I began feeling emotional toward President Bush and felt very moved and sympathetic. I didn’t expect that.”

What Jacob envies most about his brother: “He’s a better writer. He’s the one with the gift.”

What annoys him the most: “His obsession with health and safety”

JOSEPH WEISBERG

CV: Teacher, former CIA officer, 42, married, with one child. Lives in Brooklyn.

New title: An Ordinary Spy (Bloomsbury), a fictional tale about the unusual relationship between two CIA case officers

Joseph says: “[It] exposes the nitty-gritty of how the espionage industry really works.”

Jacob says: “It’s brilliant. It’s a page-turner but it also tells you what life inside the CIA is like unlike anything I’ve read before. I think it’s the real deal.”

What Joseph envies most about his brother: His writing speed

What annoys him the most: “His insistence on making more money than I do. Ever since [he was] 12 years old, when he invested in the stock market”