I've heard about Shackelford's book, but never read it. I don't know how much the book acknowledges Seth Raynor's contribution to the routing - if any - including the placement of the iconic 16th hole. Based on comments from Shackelford himself on one of the golf course architecture websites, he seems to think that MacKenzie's ego may have prompted him to refuse to use any parts of Raynor's original plan, but others think that MacKenzie must have taken elements from the Raynor routing given some early photos and the fact that Marion Hollins worked with Raynor on the early plans for the course and then worked with MacKenzie after she recommended that MacKenzie be hired after Raynor's death. Clearly, Raynor had nothing to do with actually constructing the course since it was built after his death, and Robert Hunter worked with MacKenzie on the construction. From what I've read, it sounds like Hollins, who was an accomplished women golfer, had a lot to do with making the 16th a long par 3 rather than a par 4 - and that MacKenzie wasn't easily convinced.
At any rate, these behind-the-scenes looks at CP make the course even more interesting, and the Shackelford book sounds like a great idea for a Christmas present.