In his fourth and most ambitious series for Channel 4, Niall Ferguson asks why it was that Western civilization, from inauspicious roots in the 15th century, came to dominate the rest of the world, and if the days of Western ascendency are now coming to an end. Is the West about to be overtaken by the rest? In 1683 the Ottoman army laid siege to Vienna, capital of Europe's most powerful empire. Domination of East over West was an alarmingly plausible scenario. But Islam was defeated: not so much by firepower as by science. In the second programme, The Siege , Niall Ferguson asks why the Islamic world didn't participate in the Scientific Revolution and the Enlightenment. The key question today is how far the West is still capable of maintaining its scientific lead, at a time when educational attainment in science subjects is declining.