Leading at the Speed of Growth (Catlin & Matthews) - Despite the title making me want to vomit, it has a bunch of practical advice about problems you'll encounter at various "stages" of a company, and how to identify what stage you're in.
The First 90 Days (Watkins) - Useful if you ever take on a leadership role where the current state of the organization could be described as a "shitshow".
Good Strategy / Bad Strategy (Rumelt) - Learn the difference between goals and strategy and plans.