I enjoyed Zero to One: Notes on Startups, or How to Build the Future, by Peter Thiel, more than I expected. It’s a good complement to The Hard Thing about Hard Things. Zero to One provides more guidance on what makes a startup idea more likely to be viable, while THTAHT focuses more on how to execute as a startup founder once you have your idea.
One of his core ideas is the not entirely intuitive notion that competition is more akin to socialism than capitalism. His argument is that competitive markets destroy profits. Thiel favors using proprietary, breakthrough technology to start a company that can quickly control a small market, before scaling into a legal monopoly of a much larger and/or adjacent market. His “seven questions every business must answer” is pretty good guidance for evaluating startup ideas.