Margaret Mann (April 9, 1873 – August 22, 1960) was a noted librarian and teacher who dominated the field of cataloging for almost fifty years. The bulk of her career was spent as a professor at the University of Michigan. She was hired as one of the first three full-time faculty members in the department of library science at Michigan in 1926 and retired in 1938. In 1999, American Libraries named her one of the "100 Most Important Leaders We Had in the 20th Century". Biography She was born on 1873 in Cedar Rapids, Iowa. While Margaret was known throughout her career for her breadth of knowledge and contributions to academia, it is worthy to mention that she never formally achieved more than a high school diploma. Because her family was of modest means, Margaret or "Maggie" was strongly persuaded to attend the vocational school that had just opened near her home in Chicago. She completed a two-year study in the Department of Library Economy at the Armour Institute, where she quickly impressed the faculty; after only one year of schoolwork, she was awarded with a library position. In 1897, the Armour Institute was transferred to the University of Illinois at Urbana-Champaign where Margaret continued to work for an additional six years. At this time, libraries were undergoing rapid change: "Up to the time of the World's Fair at Chicago in 1893, attention had been-I think we may safely say-largely centered in the internal management…Of course I do not mean that other matters did not occupy thought and receive attention, but we may truly say the emphasis was on the internal side. In the next few years two other matters began to forge ahead-buildings and library extension. And then followed with almost alarming rapidity a sudden expansion of the activities of the library in every external relation. First the story hour and children's work was the great discovery, then traveling libraries and commission work, then branch libraries spring up". At the library of the University of Illinois, Margaret Mann and her colleagues were integral to this transformation. When she first arrived at the library there had been no: "consistent policy of cataloging and classification…however, by the end of the first year and with the assistance only of students from the library school, all of the books had been accessioned, shelf-listed, and prepared for the shelves" This would not be the