Coleman Barks, professor emeritus at the University of Georgia, has since 1977 collaborated with various scholars of the Persian language (most notably, John Moyne) to bring over into American free verse the poetry of the thirteenth-century mystic Jelaluddin Rumi. This work has resulted in twenty-one volumes, including the bestselling Essential Rumi in 1995. He has also published eight volumes of his own poetry, including Hummingbird Sleep: Poems 2009–2011 (2012) and Winter Sky: Poems 1968–2008 (2008), both from the University of Georgia Press.