Is that a snake or a coiled rope? Intriguingly, that is the question which starts Professor Sunil Khilnani's look at the life and legacy of Adi Shankaracharya, the philosopher and theologian who set Hinduism - the third largest religion in the world - on a new course. Shankaracharya's ambition was to provide a unified, coherent, single reading of the Hindu scriptures. His teachings were not universally embraced but they were revived by Indian nationalists looking for a muscular response to the monotheistic religions of Christianity and Islam. His efforts to capture the oneness of the universe produced beautiful, sometimes enigmatic sentences - as elusive as the man himself. "I am neither earth nor water nor fire nor air nor sense-organ nor the aggregate of all these," wrote Shankaracharya, "for all these are transient, variable by nature." Produced by Mark Savage Listeners can catch up with the series and see the list of remarkable Indians featured on the Radio 4 website.