The Code of Canon Law for the Latin Church, which became effective in 1983, is a revision of the Codex juris canonici [code of canon law], promulgated in 1917. The code itself, the culmination of centuries of legal growth, consists of 1,752 canons in seven books and supersedes all previous compilations. It does not contain all canon law, which continues to grow, but it is the base of the present-day law, and the study of canon law consists mainly in mastering the code and its application. Canon law lays down rules for the governance and regulation of the clergy and the church, including such matters as the qualifications, duties, and discipline of the clergy and the administration of the sacraments (more particularly the laws regarding holy orders and the sacrament of marriage). Canon law embraces both general laws applicable in the church universal, such as those on requirements for the priesthood and those on marriage, and local laws applicable only in certain dioceses.