This is a long review, tl;dr version: Some people just know how to write commentaries, and Gordon Wenham is one of those people.
Pity the book of Numbers, not only is it rarely read by Christians, but it is probably even more rarely preached by pastors. I mean, you've got lists of people and weird rituals, and even more lists of people and more weird rituals, sandwiched between a travelogue with some recalcitrant people who don't really seem to enjoy being in the wilderness. Why IS this book in the Bible? After you finish reading Gordon Wenham's commentary, you will understand why Numbers is there and very much worth reading and studying.
Three things stood out to me as I read through Mr. Wenham's commentary:
1. The importance of ritual. In the introduction and then some in the body of the commentary, Mr. Wenham points out the importance of ritual (or rather he points us to an anthropologist who points us to its importance). A society's rituals reveal its most deeply held beliefs and customs, the only problem is, the rituals are so well known and understood to that particular culture, no one ever feels the need to explain them. (Example A: Why does everyone sing the exact same song at every sporting event in America? What is that all about?)
We have the exact problem in Numbers. There are all these rituals and ways of approaching and worshipping God, but no one ever stops to explain why the rituals are important or how exactly they do what they do. This is part of the difficulty of understanding Numbers, and if we miss this, we will miss the entire book. Mr. Wenham helps us here.
2. The flow of thought through the book. I cannot believe how often this is neglected by many commentators; Mr. Wenham is constantly asking the question, "why is this ritual, or list of people, or historical event, recorded in this particular place in the book?" This helps us understand that Numbers was written as a particular literary piece with a theme and format in mind and everything contained in it, fits into that theme and has its specific place in Numbers for a reason.
3. Numbers point us forward to Christ. Mr. Wenham constantly asks the question, "how does this ritual or event or list fit into the coming of Christ in the New Testament? How did the NT writers use this book?" Numbers wasn't written in a vacuum and the NT authors believed it was there for a reason beyond just recounting how the children of Israel survived in the wilderness. Mr. Wenham's references to the NT help us understand Numbers in light of future revelation and the advent of Christ.
It's a good commentary and blessedly spare to boot.