Classical Chinese
With Naiying Yuan and Haitao Tang, he co-authored several textbooks on classical Chinese, notably "The Grammar of Classical Chinese: A Basic Introduction", "Classical Chinese: A Basic Reader" (1994), "Readings in Classical Chinese Poetry and Prose" (1994), "Selections from Classical Chinese Historical Texts" (1993), and "Selections from Classical Chinese Philosophical Texts" (1993). After his death in 2004 the Princeton University Press published new versions of all volumes as "Classical Chinese: A Basic Reader", revised and updated by Geiss's coauthors Yuan and Tang.