His best-known works include "Greek Buddha: Pyrrho's Encounter with Early Buddhism in Central Asia" and "Empires of the Silk Road: A History of Central Eurasia from the Bronze Age to the Present." "Greek Buddha" examines links between very early Buddhism and the philosophy of Pyrrho, an ancient Greek philosopher who accompanied Alexander the Great on his Indian campaign. The book is noted for its challenging and iconoclastic approach to multiple issues in the development of early Buddhism, Pyrrhonism, Jainism and the Śramaṇa movement. "Empires of the Silk Road" is a rethinking of the origins, history, and significance of Central Eurasia.