A more accurate review would be 4.5 stars.
Wellum is a sharp theologian, and this book is a fine defense of Jesus' identity (as the divine Son of God and Prophet, Priest, and King) and his work in saving his people. In particular, this is a fine defense of penal substitutionary atonement (PSA), a doctrine that some find offensive (likely because they cannot bring themselves to acknowledge how offensive sin is to God, and how it must be dealt with decisively, and even violently). The biblical evidence for PSA is clear. And other aspects of the atonement rely on PSA. Jesus is an example, but if his death didn't actually accomplish something, it's a strange example to follow. It would be a pointless sacrifice. Christus Victor, the idea that Jesus, in dying on the cross and rising from the grave triumphed over his enemies, including Satan, doesn't work without PSA. Satan wanted to get people to rebel against God, and he is also the accuser, pointing out our sin and trying to have us believe that we could never be forgiven. He is defeated because Jesus takes our sin on his shoulders, is regarded as sin itself, pays the penalty in full for the sin of all who trust him, and then rises from the grave.
Where this book falls a bit short is defending the idea of exclusivity. I saw some marvel that Wellum would present a brief tour of Enlightenment philosophy, but that tour is superficial and doesn't get to the heart of today's arguments against exclusivity. I would rather focus on the fact that all of us believe in exclusivity, at least in some things in life. People who might find the exclusivity of Christ offensive surely believe, quite exclusively, that racism is wrong. We all make exclusive truth claims. The claim that only Jesus is the God-man who can reconcile us to God, and that we must have conscious faith in him to be saved, is exclusive, and it is true, just as exclusive and true as the claim that two plus two is four and not three or five.
As with the other books in this series, I wish Zondervan had printed these using better paper (the paperback has paper that feels like a thicker version of newspaper; I don't think it will age well) and a hardcover or casebound binding. These books were printed for the 500th anniversary of the Reformation, but they deserve to have a long shelf life.