In Judaism, prayer books contain texts of daily and festival prayers. During the tannaitic and amoraic times, prayer books did not exist, and all prayers were not by heart (Ber. 5. 3-5). However, by the geonic era, prayer books began to be produced. The book containing regular prayers is known as the Siddur. Other books contain both daily and festival prayers. Various Jewish sects such as the Ashkenazim, Sephardim, Hasidim, and the Progressive produce their own version of prayers which meet their specific needs of worship. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 764