Charles Walgreen was a major influence on Chicago economics, both leading witch hunts against unreliable academics and funding others, including George Stigler, who used these resources to significantly shape the discipline of economics. Here is another take on his career.
Okrent, Daniel. 2010. Last Call: The Rise and Fall of Prohibition (New York: Simon and Schuster).
197: Charles Walgreen ... who built his Chicago-based chain from nine locations in 1916 to twenty four years later. In 1922, Walgreens introduced the milk shake, which family histories have credited the chain's next growth spurt. But it's doubtful that milk shakes alone were responsible for Walgreens rocketing expansion from 20 stores to an astonishing 525 during the 1920s. Something Charles Walgreen Jr. told an interviewer many years later suggests another possibility. The elder Walgreen worried about fire breaking out in his stores, his son recalled, but this apprehension transcended concern for his employees: he "wanted to get in as fast as possible and to get out as fast as possible, Charles Jr. remembered, "because whenever they came in we'd always loose a case of liquor from the back."