Peter Thiel's Zero to One was outstanding. Its advice was actually different from most other entrepreneurship books out there. It's most appropriate for startups trying to make it big (i.e. become "unicorns").<p>Ben Horowitz's The Hard Thing About Hard Things is a great startup managerial book. It chronicles Ben Horowitz's struggles as CEO of LoudCloud. Probably most appropriate for more mature startups.
The phonebook, because it has customers and your competition.<p>Nothing has helped me grow more than <i>actually running a startup</i> a couple of times.<p>If you're just looking for startup-themed books, I'd honestly suggest <i>Masters of Doom</i>, <i>Dreaming in Code</i>, and <i>Soul of a New Machine</i>.<p><i>Lean Startup</i> if you're feeling trendy.