[Jtsummers]

I'd recommend reading The Goal and, optionally, Critical Chain before The Phoenix Project. It sets up a lot of the context of the ideas around theory of constraints that The Phoenix Project builds on, but doesn't delve into. I read them in the order of The Goal, The Phoenix Project, It's Not Luck, Critical Chain. I found that the last book gave some useful insights into things that The Phoenix Project presented. On the other hand, after recommending these books to colleagues most only read The Phoenix Project and they seemed to not grasp (as it wasn't the core of the book) theory of constraints as well until they later read The Goal (or heard about it enough from me).