Calame and Rhodes on McCoy is a must. It is a unique contribution to the Cooper literature, and is also a gem in the pantheon of true-crime accounts by a cop. It is well-written and touches on subjects that the FBI would not allow their agents to write about these days. A treasure for all time.
Barb Dayton. Yes. Get the second edition copy of Ron and Pat Forman's book. It is more complete, has a ton o' pix, and is better written. Is Barb DB Cooper? I doubt it, but Barb was a fascinating person and her confession is one of the best analyses of how DB Cooper could have done the caper successfully.
KC. Well, if you want to know all the principals in the cat fight over at the DZ, then you gotta read this book. But it's basically trash and filled with inaccuracies and woeful assumptions.
Max's book is a fun read. I read the copy from my library. Besides, the main character Clara says she and DB Cooper lived just down the road from me at Hofstra University, so that was cool.
DB Cooper's Parachute I've never read and it is doubtful I ever will. If you do, let me know.
Similarly, you can skip Bradley's book about his dad, or read my synopsis at the MN. Forget Grey Cop, etc....