The worst leadership advice I have ever read came from a leadership book. It was confident, well-structured, and completely useless in the one situation I bought it to handle. Over time I noticed that almost everything I actually use as a leader, I picked up somewhere else entirely, usually from a book that had nothing to do with business at all. So I stopped reading books about leading and started reading more or less everything else, and I became a better leader for it.
I want to be honest that your list will look nothing like mine, because the point is not the specific titles. The point is the angle. The books that taught me the most about running a company were never trying to teach me anything about running a company, which is exactly why the lessons stuck.
Why business books mostly fail
A business book has a problem built into its premise. It has to flatter the reader, justify its own thesis, and pretend the messy thing it describes is more orderly than it is. So you get a tidy framework, three case studies chosen because they fit, and a confidence the real world rarely supports. You finish it feeling informed and act no differently on Monday.
A great novel does the opposite. It refuses to simplify people, and leading people is most of the job.
The five that did it for me
If you forced me to name them: Marcus Aurelius on staying composed when everything is on fire, which is most weeks. A serious history of a hard decade, because nothing teaches decision-making under uncertainty like watching real people make irreversible calls without knowing how it ends. A novel that made me feel the inside of a life unlike mine, which is the closest thing to a superpower a manager can have. A book about how science actually gets made, all the wrong turns the textbooks edit out. And one quiet book about attention, because protecting it turned out to be the whole game.
You should swap every one of those for your own. The category matters more than the title.
The best leadership ideas I have rarely arrived dressed as leadership ideas. They came in through the side door, from a book about something else.
What outside reading actually trains
Reading widely does something a business book cannot. It builds the muscle for holding a complicated situation in your head without rushing to flatten it into a framework. It grows the empathy that leading people actually requires. And it keeps reminding you that the smartest people in history were usually wrong about something, which is a useful thing to carry into a room where everyone expects you to be certain.
I protect my reading time the way I protect the rest of my recovery, because it is recovery, and it is also the most reliable source of ideas I have. The habit is simple. Read mostly outside your field, read things that are better than you, and trust that the lessons will find their way to the right problem on their own. They reliably do.