James Bieri (born 1927) is a psychologist and biographer who introduced in 1955 the concept of cognitive complexity, derived from his doctoral study with George A. Kelly. Subsequently, integrating ideas from information theory and psychophysics, Bieri and his research team at Columbia University published a volume entitled Clinical and Social Judgment (John Wiley, 1966).^[1]

After serving in the U.S. Navy, Bieri obtained his undergraduate degree from Antioch College (1950) and his Ph.D. at Ohio State University (1953).

Upon retirement, Bieri pursued his interest in English Romantic poetry and in 2005 published a two-volume biography of Percy Bysshe Shelley (University of Delaware Press, 2004 & 2005). A second edition of this work was published in 2008 by Johns Hopkins University Press.