NEW YORK—Ed Klein, known for his best-selling takedowns of Barack Obama and Hillary Rodham Clinton among others, has signed up for two more books.

Klein has an agreement with William Morrow for books on the powers behind "the left-wing political agenda" and on the 2016 presidential nominee of the Democratic Party. Klein's Obama book, "The Amateur," topped The New York Times' hardcover best-seller list this summer. It was released by the conservative Regnery Publishing.

Morrow, an imprint of HarperCollins Publishers, announced the deal Friday.