Van Riper, who later divorced and switched back to her maiden name of Ruth Lilly, is the last surviving great-grandchild of Col. Eli Lilly, founder of Eli Lilly and Co., the pharmaceutical giant. At 87, she is a very low-profile, ailing billionaire-philanthropist who will now alter the 700-square-foot world of the four-person magazine housed in the basement of Chicago's Newberry Library.