This is a detailed outline of the extinction dilution method from:\u00a0Nagasaki, K., and G. Bratbak. 2010. Isolation of viruses infecting photosynthetic and nonphotosynthetic protists, p. 92\u2013101. In S. W. Wilhelm, M. G. Weinbauer, and C. A. Suttle [eds.], Manual of Aquatic Viral Ecology. ASLO.Please see the published manuscript for additional information.