Juan E. O'Leary was a dedicated educator, an essayist, a journalist, an historian, a politician, and a poet. He was one of the earliest twentieth-century Paraguayan poets, and he was also one of the founders of modern Paraguayan culture. Charles R. Carlisle in his introduction to Beyond the Rivers: An Anthology of Twentieth-Century Paraguayan Poetry (1977), calls O'Leary the "Dean of Paraguayan literature." O'Leary's popularity in large part resulted from the patriotic and historical themes in his poetry and essays, which were motivated by the huge human and territorial losses suffered by the Paraguayan people during the War of the Triple Alliance, fought against Argentina, Brazil, and Uruguay between 1865 and 1870. Another dominant theme in O'Leary's poetry was the defense and glorification of the Guaraní people, the native Indian inhabitants of Paraguay.

A prolific essayist, O'Leary collaborated on nearly every new Paraguayan publication, contributing both poetry and prose. He...