If you enjoyed the book The Bottleneck Rules, a longer version, in novel form, is The Goal by Eli Goldratt.
It's a manufacturing classic. The book follows the manager of a production plant with problems completing orders on time. By walking you through some counter-intuitive examples, you can see how a better manufacturing facility would work. One example? Not everyone in the factory should be busy every second of every day.
The book eventually reaches a point where it recommends three key metrics for a manufacturing plant: Throughput, operational expense, and inventory. These are the main items to keep an eye on to see if your factory is running well.