This study investigates the symbolism of the hatta't offering in the priestly literature of the Pentateuch, especially Leviticus. It starts by discussing the relationship between the occasions for bringing hatta't and its basic function, with special reference to J. Milgram's thesis that the hatta't purifies only sancta and not persons. The examination of the relevant texts shows that his view is one-sided. The hatta't deals with both hatta't (sin) and uncleanness; when sancta are purified, so is the offerer (chapters 1-2). A deeper dimension of 'purification' is set out in Lev 17:11 (chapter 4) and is manifested in contagion of the hatta't, viz. setting substitutionary death over against death caused by sin and uncleanness (chapter 5). Exegesis of Lev 10:16-20 (chapters 2-3), a crux interpretum, forms the basis of inquiry into the various types of hatta't ritual, opening up the possibility that behind the variety of atonement ceremonies in Leviticus there is a coherent system. The episode in that section shows the inadequacy of the eighth-day service in the face of Nadab and Abihu's sin and adumbrates the ritual in Lev 16 (chapter 3). Then from Lev 10:17 and other texts it is inferred that the concept of kipper includes 'purification' and 'bearing guilt' (chapter 4). It is argued that the modes of blood manipulation in the hatta't depend on the nature of the occasion, whereas the modes of disposal of the hatta't-flesh hinge on whether the agent of atonement is also its beneficiary (chapter 5). These conclusions provide a rationale for the Azazel-goat ritual (Lev 16). By purifying sancta Aaron bears guilt. Then that guilt is removed from the sanctuary by the Azazel goat when Aaron confesses the sins of all the Israelites over it and sends it away to Azazel (chapter 6).