Christ in the Old Testament?

If Genesis 3:15 really is the 'proto-gospel,' after which everything in the Bible is one grand story of good news anticipating our coming Redeemer, then we should expect to be able to discover anticipations of Christ throughout the Old Testament. One major way God inspired the biblical writers to do that was through 'typology'. Unless we understand typology, much of the Old Testament will remain either useless ancient history or a perpetual mystery. So, what is typology? One of the best explanations is given by OT scholar Michael Barrett:

"...typology is not an interpretation technique arbitrarily imposed on the Old Testament in an effort to rescue it for Christian relevance. Rather, it is a method of divine revelation. Let me put it simply in terms of 'x' and 'y'. If x is the picture and y is the truth, God was saying to look at x in order to understand something about y. Much of what we read in the Old Testament is God's using x's to teach ultimate truths about y. The principle thing to remember is that x does not equal y. So x is the type, the object lesson [e.g. the Tabernacle] that foreshadows or predicts the actual, future realization of the pictured truth. Y is the antitype, the future realization to which the type points [e.g. Christ, the ultimate Tabernacle of God's atoning presence. See John 1:14]. The type represents and resembles the antitype. This does not mean that x loses its significance or usefulness in [its original context, but it points beyond itself to something far greater]. The key point is that Christ is the ultimate reality: He is the Idea behind - or perhaps I should say above - all the visible impressions."

- Michael Barrett, Love Divine and Unfailing, p. 11.