He received his PhD in 1985 at Indiana University Bloomington, and since then has continued to do research on Central Asian Islam, particularly Sufism and its political and social dimensions.
He has published major studies of Central Asian religion and history using Persian, Arabic and Turkic manuscript sources he has painstakingly accumulated from collections all over the world.
He is one of a small group of scholars, including Jürgen Paul, Adeeb Khalid, Robert D. McChesney, Jo-Ann Gross, Ashirbek Muminov, Maria Subtelny, Beatrice Forbes Manz, and Stéphane A. Dudoignon, who have worked seriously to debunk prevailing essentialist and ahistorical stereotypes about Sufism, Islam, and politics in the history of Central Asia.
Like a very few Central Asian scholars before them, these experts work with equal facility on Arabic, Persian and Turkic, but have also developed working methods that understand concepts and practices of Islam and Islamic communities on the believers' own terms, rather than through biased and invariant concepts.
It also examines pre-Islamic religious life in Inner Asia, the use of narratives as foundational myths, and the role of Islam and conversion in identity formation.