Abu Bakr al-Baghdadi, the leader of IS. In July of 2014, he announced that he had become the caliph, the supreme leader of the Islamic world, and he demanded the allegiance of Muslims throughout the world. Immediately after his appeal, in Indonesia - the country with the largest Muslim population - hundreds of young believers pledged their allegiance at a rally in Jakarta. From Western countries as well, thousands of young people have joined the ranks of the IS fighters. In the United Kingdom, a group that supports IS openly recruits young people. Young immigrants who suffer discrimination, as well as other disaffected British citizens have come under the sway of the IS ideology that "for Muslims, to live under the caliphate is a duty, and to live under man-made laws is prohibited". How did Baghdadi build the extremist organization that now poses a threat throughout the world? Secret American documents and the testimony of former military officials shed light on how IS took advantage of American missteps to grow exponentially. The mysterious Baghdadi was imprisoned by U.S. forces twice after 2004, and he was held at a detention center in southern Iraq. He was converted to extremist Islamic thought while in detention, and it was there that he met many of those who later became leaders in the IS organization. The growth of IS was further stimulated by the conflict between the Shia and Sunni sects that intensified under U.S. occupation policies. The extremist ideology of IS has spread throughout the world. We explore this reality and the American missteps and miscalculations that lay behind the birth of IS.