revision preference src: Isherwood also introduced Gruber to his landlady, Evelyn Hooker. Evelyn Hooker, a Evelyn Hooker, pioneered research into sexual orientation that contributed to the removal of homosexuality as a mental illness from the Diagnostic and Statistical Manual of Mental Disorders. <SEP> tgt: Isherwood also introduced Gruber to his landlady, Evelyn Hooker. Hooker, a psychologist, pioneered research into sexual orientation that contributed to the removal of homosexuality as a mental illness from the Diagnostic and Statistical Manual of Mental Disorders.