Margaret Brooks Church (1889–1976) was an American mycologist who specialized in Aspergillus and other fungi involved in food fermentation.[1] She co-authored the first manual on Aspergillus with Charles Thom and worked with Thom on his treatise on Penicillium.[2] She was the first westerner to study the ang-khak fermentation of rice using Monascus purpureus (see: Church, 1920), and studied other Asian soy fermentations involving the fungus known as Aspergillus oryzae. This research culminated in her writing a USDA bulletin entitled Soy and Related Fermentations in 1923. In 1928 she took on a role as the Head of Biology at Urbana University, Urbana, Ohio, before her retirement in 1939.