Leviticus is the third book of the Hebrew Bible/Old Testament, a priestly law code belonging to the Pentateuch and central to the ancient Israelite sacrificial and purity tradition. Its core content divides into two broad concerns: the first half (chapters 1–16) prescribes the mechanics of the sacrificial system — burnt offerings, grain offerings, peace offerings, and sin offerings — along with the ordination of Aaron's priesthood, dietary laws distinguishing clean from unclean animals, and elaborate protocols for diagnosing skin diseases and bodily discharges. The second half (chapters 17–27), sometimes called the "Holiness Code," shifts from ritual procedure to ethical and social law, covering sexual prohibitions, obligations to the poor and foreigner, the sacred calendar of festivals, the Jubilee year's land-redistribution mandate, and the terms of the covenant with its blessings and curses. The book's animating claim is that Israel must be holy because its God is holy — purity, sacrifice, and right conduct are not merely administrative rules but the means by which a human community maintains proximity to the divine presence dwelling among them. Distinctive among biblical books, Leviticus treats the body, food, disease, and economic relations as theological categories, making it essential reading for understanding both ancient Israelite religion and the later development of Jewish law, Christian theology of atonement, and debates about biblical ethics.