I very easy read, and a clear explanation of what lean is. It's not a thick book (160 pages), but the main ideas could have been described in a lot fewer pages. The book clearly describes the difference between resource-optimized and flow-optimized systems, including easy to understand examples.
The most valuable parts for me were chapter 3, describing Little's law, the law of bottle necks and the law of variation, and chapter 4, where the key insight is that in a resource-oprimized system there may be a lot of work done that would simply disappear if the system instead was flow-optimized. ( )

Management, Modig N