At the first year of my career, many have told me that you cannot be a developer for forever. At some point, you will have to move up.
I am lucky that I did get move up, but what is an engineer's manager, a tech lead, a VP of engineering, or a CTO? In this book, it explains their roles, expectation from the top, and from the ones they are managing of.
It helps me to understand more about these possibilities.