JI was formed in 1993 by Abdullah Sungkar and Abu Bakar Ba'asyir after the two leaders split with the leadership of Darul Islam, a jihadist movement in Indonesia. Sungkar was the central figure in the ideology and operations of JI until his death in 1999. Ba'asyir provided inspirational leadership after Sungkar's death, but was weak in operational leadership. A radical operational wing developed in JI under the leadership of Hambali in Malaysia and Singapore. This wing pursued violent, terrorist activities under funding connections with al Qaeda. Hambali's terrorist group was responsible for all of JI's terrorist attacks in the years 2000-2003. This included seven bombing attacks designed to foment violence between Christians and Muslims, with the intent of expediting the institution of Islamic law in Indonesia. There is no evidence that madrassahs (Muslim schools) in general produce terrorists. Still, there is evidence that JI-linked radical madrassahs, a small segment of the madrassah population in Indonesia and Malaysia, are linked with both participation in JI terrorist attacks. Key parts of JI's networks are increasingly family-oriented. As organizations similar to JI continue to decentralize and splinter, kin relationships provide the glue that holds these groups together. This will make efforts to penetrate and disrupt these organization more difficult in the future. 8 figures and 20 notes