Mary Loos a stroke. Mary Loos Mary Loos (May 6, 1910 – October 11, 2004) was an American actress, screenwriter and novelist. She was occasionally credited under her full name, Mary Anita Loos. Born in San Diego, she was the daughter of Dr. Clifford Loos, co-founder of the Ross-Loos Medical Clinic and the Ross-Loos Medical Group, the first Health maintenance organization (HMO) in the United States. She was the niece of screenwriter Anita Loos. She was both co-creator and one of the writers for "Yancy Derringer" (1958-1959), an American Western TV series. Mary Loos died in Monterey, California, aged 94, due to
Anita Loos his time-worn histrionics, she made certain Emerson understood he would not be joining her in New York under any circumstances. Once again at home in New York, she and her old friend screenwriter Frances Marion, worked on an unproduced play for Zasu Pitts. A few romances came her way, including Maurice Chevalier. Two Broadway producers had their eye on a musical version of "Gentlemen Prefer Blondes" and brought in Joseph Fields as co-author. After initial stops and starts, Loos threatened to quit the production unless they assured her she would never have to speak to Fields again. The show opened