Jonathan Butler, once a financial journalist, launched the real estate website Brownstoner, co-founded the Brooklyn Flea and launched Smorgasburg, the largest outdoor food market in the nation.

Butler’s latest endeavor was writing the book “Join the Conspiracy: How a Brooklyn Eccentric Got Lost on the Right, Infiltrated the Left, and Brought Down the Biggest Bombing Network in New York.”

He joined anchor Stef Manisero on “Weekends on 1” to discuss the book Sunday morning.