Accelerate : The Science Behind DevOps

Great reference guide for what does and doesn't work, and what does and doesn't have a good scientific basis. A bit dry, but if you're willing to put the effort in you're going to get some great information to direct your processes.

Edit: I've found myself recommending this to a few other people and using it as a reference a number of times, so I am bumping my rating to 5 stars.