Dating from the 5th century BC, The Art of War is still a reference not only in a war context, but for life in general. As one of the most important books on military strategy and tactics, this book goes beyond war and its strategies and tactics. 13 chapters with rules that you may or may not disagree with, but one thing is for sure: it doesn't matter what you do for a living, this book will guide you to the importance of planning, strategy and context.
Planning: Everyone's aware of its importance, but to be successful you need to master your assets and your enemy*.
Strategy: Ok. You know what's on the table, now learn to analyze your strengths and weaknesses , set your goals and you're ready to go to war.
Context: Your strengths, your weaknesses, your plan, your strategy might be enviable, but a small change can turn into catastrophic results. Acknowledge where, what and when and combine that with your plan and strategy if you want to succeed.
Sun Tzu has this in your face approach that I've tried to apply so far. And it's only with this kind of pragmatism that you're able to set rules. Sun Tzu wrote these 13 chapters with great confidence and the truth is that after more than 2000 years after, guys like me will be nodding its head while reading his words.
*Enemy In Sun Tzu's context; your's probably different. See the enemy as a metaphor to adversities and challenges in your life.