Rabbi William Rosenau (1865-1943), born in Wolstein, Germany, was a leader of Reform Judaism at the beginning of the twentieth century in the United States. He emigrated with his parents to the United States in 1876, settling in Philadelphia. He received a B.A. from the University of Cincinnati and a Ph.D. from Johns Hopkins University. He also got rabbinic ordination from Hebrew Union College. He served as rabbi in Omaha, Nebraska and in Congregation Oheb Shalom of Baltimore, Maryland. He was also on the faculty of Johns Hopkins University. Among other Reform rabbis of his time, Rosenau was considered one of the "radical reformers" in relation to traditional Jewish ritual. He was an editor of the revised editions of the Union Prayer Book and the Union Haggadah.