Rap, movie (Set It Off), and TV (Fox's "Living Single") star Queen Latifah has just signed with William Morrow editor Doris Cooper to write an inspirational book on self-esteem. World rights for the hardcover, acquired in a rumored low-six-figure deal negotiated by agent Denise Stinson, is tentatively titled From the Heart of a Queen and will be published in 1998. Cooper also recently acquired Daily News writer Denene Millner's The Sistahs' Rules -- about how to find "Brother Mr. Right" -- and will release it as a paperback original this September.