This is part of a larger project reviewing commentaries on each book of the Bible. Follow the links from that post for more information on the series, including explanations of what I mean by some of the terms and abbreviations in this post. You can see my annotated Amazon Listmania! list of Leviticus commentaries if you want a quick overview of what I think are the most important commentaries (or at least what I thought when I made the list) before looking more deeply at this more detailed review.
Gordon Wenham (NICOT, 1979) has my favorite commentary on this difficult book. Wenham is especially strong on understanding the theological significance of cleanness/uncleanness, holiness, and other ritual matters. It's not as detailed as some of the following commentaries, but I think it's the best starting place for a pastor or Bible teacher. He's got a good sense of the symbolism behind most of the laws that sound very strange to the modern ear and what they would have meant to Israel. He ends each section with some reflections on connecting the material he's just discussed with the New Testament. Especially helpful are his explanations of how the New Testament authors would consider the various festivals and sacrifices as fulfilled in Christ in different ways. I thoroughly enjoyed working through this commentary. Wenham spends little time speculating on source critical issues, due to the circularity of most such arguments and the wide divergence of source reconstructions among those who spend their time making what flimsy consensus there is even less of a consensus.