Arthur C. Nielsen Jr., the man who turned the A.C. Nielsen Company into a global leader in market research and television ratings, has died at the age of 92. Nielsen's father founded the company in 1923 and was known for spearheading much of the innovation behind it, but it was the younger Nielsen who led the firm to prominence, after joining in 1945 and taking over as president in 1957. In 1948, he convinced the firm to devote $150,000 to building the first general-purpose computer, the Univac. Building off of his father's revolutionary TV audience measurement system, he later expanded A.C. Nielsen's reach to new areas, including the development of a coupon clearinghouse and data-tracking services for magazines and even oil wells. Perhaps his most impressive achievement, however, was his ability to maintain A.C. Nielsen's position as the nation's pre-eminent TV and media ratings firm, even amidst the proliferation of cable networks.Arthur "Art" Nielsen stepped down from his role as chairman of the company in 1983, a year before orchestrating its sale to the Dun & Bradstreet Corporation for $1.3 billion in stock. Throughout the course of his illustrious career, he served on the board of more than 20 companies, including Motorola and Walgreen, and advised three US presidents. But his life's work and lasting legacy could just as well be summarized by a simple proverb he learned from his father: "If you can put a number on it, then you know something." Arthur C. Nielsen passed away on October 4th in Winnetka, Illinois. He is survived by three children and seven grandchildren.