L. C. Dunn (1893-1974) spent most of his scientific career conducting research in developmental genetics as a member of the Zoology Department at Columbia University in the City of New York. He had an accomplished scientific career researching mutations in mice, which earned him respect from other geneticists and scientists. Genetics research, however, was only one aspect of Dunn's activities. He also campaigned for political and social rights, usually focusing his attention on problems pertinent to scientists and science. Guiding Dunn were his beliefs in socialism, democracy, and intellectual freedom, as well as his humanitarianism. He effectively participated on campaigns in two ways, remaining out of the public eye by performing committee work and entering the public sphere by publishing and lecturing. Dunn did not act alone, but rather was a member of various networks forming an active community of intellectuals. Together these scholars organized privately and acted publicly in an effort to combat what they viewed as society's injustices, and through their intellectual and political participation they shaped American society. This dissertation focuses on Dunn's professional years from the 1920s to 1950s and explores L.C. Dunn's role as a socio-political activist among a community of scholars.