More than half of the mushrooms in the United States are grown in and around the town of Kennett Square, Pennsylvania, which calls itself the "mushroom capital of the world." Walter W. Maule (1892-1964) and Charles C. Brosius (1930-), both Chester County, Pennsylvania, mushroom growers, were active in professional trade associations and advocates for their industry. This small collection on the mushroom industry consists of papers that document mushroom industry educational courses and professional trade associations. The collection provides insight into the role profession trade associations such as the Mushroom Growers Cooperative Association, the Mushroom Cooperative Canning Association, and the American Mushroom Insitute agriculturual play in affecting legislation and mushroom farming practices.