Islamic law is often said to be very pluralistic due to its interpretational variations. At the level of sources, however, accounts of Islamic law have generally emphasized the reliance on a set of major 'roots' of law, with other lesser sources. This paper discusses on the case of Nizari Ismaili law in historical as well as contemporary terms, elaborating its authority structure, especially the concept of Imamat and role of the Imam, as well as using it to strengthen the case that plurality in Islamic law can and should be extended to a plurality of sources as well as of rules.