The lack of new Star Wars material ended with the 1991 release of Timothy Zahn's novel Heir to the Empire. Heir to the Empire, which reached #1 on the New York Times Best Seller list, began what would become a large collection of works set before, between, and especially after the original films. StarWars.com wrote in 2014 that the novel "jumpstarted a publishing program that endures to this day and formalized the Expanded Universe". It introduced, among others, the popular characters Grand Admiral Thrawn and Mara Jade, and was followed by the sequels Dark Force Rising (1992) and The Last Command (1993). The Thrawn trilogy is widely credited with revitalizing the Star Wars franchise. In The Secret History of Star Wars, Michael Kaminski suggests this renewed interest was a factor in Lucas's decision to create the prequel trilogy.
