In 1980, Warren left employment at the "Digest" to become a full-time writer. She moved back out West to pursue research on her next novel, a Western historical opus. It appeared from Ballantine in 1991 under the title "One Is the Sun". Eventually settling in southern California, she made the decision to go independent with book publishing. The result was Wildcat Press, which has published all her books since, including her 2001 novel, "The Wild Man", inspired by her years in Spain; she had traveled there regularly during Francisco Franco's regime when she was liaison to the "Digest"'s Spanish edition.