halakah or halacha (both: häläˈkhä, häläkhäˈ) [key] [Heb., = law], in Judaism, the body of law regulating all aspects of life, including religious ritual, familial and personal status, civil relations, criminal law, and relations with non-Jews. Halakah is the term used to designate both a particular ordinance and the law in the abstract. The adjective halakic means "of a legal nature." The plural, halakoth, designates a collection of laws. It usually refers to the Oral Law as codified in the Mishna and, in particular, to those statements of law that appear in categorical form without immediate regard for scriptural derivation. The most authoritative codifications of these laws are the Mishneh Torah of Maimonides and the Shulhan Arukh [the set table] by Joseph Caro. Halakah was the important unifying force in world Jewry until modern times, when its authority was challenged by religious reform and secular conceptions of a Jewish nation. Contemporary problems in halakah revolve around its application to technological change, especially in relation to medical issues and Sabbath observance. Halakah is contrasted with aggada (plural aggadoth), the literary, aesthetic elements in the Oral Law and in the Talmud, and Midrash generally, which elaborates scriptural meaning through legends, tales, parables, and allegories. Both the halakic and aggadic elements have been extracted and made the subject of commentary.