Complex sentence: Harcourt also published mass-market paperback books with Pyramid Books, which it bought out in 1974 and renamed Jove Books, and eventually sold to the Putnam Berkley Group in 1979.
Split into simpler sentences: Harcourt also published mass-market paperback books with Pyramid Books, which it bought out in 1974 and renamed Jove Books. It sold this section to the Putnam Berkley Group in 1979.