On Liberty
While this is an old book, it is one of the pillars of the utilitarian approach.
The book itself presents itself like an ethics manual. Some things can be traced back to the foundational principles of religions. It puts a lot of eyes on how the individual behaves and how it should commit toward the welfare state.
It is a must to understand how the way we navigate in society was predicted and planned almost 200 years ago. Like it or not, some of the movements we see in societies today (from the capital to the state) are just implementations of a form of this speech.