Genealogy has been counted a subdivision of the science of history and a section of unlettered Arab`s historiography. Some causes like compiling divan, widespread victories and A`rab`s settlement in captured lands, spreading of competitions and prejudices, this inheritance of the unlettered Arab`s age grew rapidly and thereof genealogists and some sources appeared. As the field was in close relation with Imamate and the household of the Prophet, Shi`ite Imamyyeh and Ali`s descendents has played a considerable part in its progression. In yhe paper, an outlook of the field has been presented and the role of Imamyyeh has been described.