The Sefer Abudarham is a popular 14th-century compilation of laws, customs, and commentary on the prayer book, named for its author, Rabbi David Abudarham. In his introduction, Abudarham explains that he was motivated to write the book because he felt that the masses were unequipped to understand the content of the prayers they muttered or the surrounding customs. The work draws on a wide array of earlier materials and incorporates commentary on the Passover Haggadah as well as a systematic explanation of the Hebrew calendar. It is considered a central text on prayer, published in many editions and quoted frequently in later works.