Ovadia Yosef was an Iraqi-born Talmudic scholar, a posek, the Sephardi Chief Rabbi of Israel from 1973 to 1983, and a founder and long-time spiritual leader of Israel's ultra-Orthodox Shas party. Yosef's responsa were highly regarded within Haredi circles, particularly among Mizrahi communities, among whom he was regarded as "the most important living halakhic authority".

In Jewish law, a posek is a legal scholar who determines the application of halakha, the Jewish religious laws derived from the written and Oral Torah in cases of Jewish law where previous authorities are inconclusive, or in those situations where no clear halakhic precedent exists.