There are more than a million business books in print, and thousands more published every year. But what if, for some reason, you were only allowed to read nine books about managing people? (Why nine and not 10? I’ll explain at the end of the post.)

After giving it a lot of thought, here are the nine that I would recommend: 

The Effective Executive
Subtitle: The Definitive Guide to Getting the Right Things Done
Author: Peter F. Drucker

Why it’s a must read: This book is literally definitive in the sense that it definesmanagement at the executive level so clearly that most other serious management books takes this book’s concepts for granted. The Effective Executive also rejects the concept that an executive should encourage a personality cult among employees and the press. For Drucker, management means getting things done without grandstanding or being concerned about your public visibility.

Best quote: “Men of high effectiveness are conspicuous by their absence in executive jobs. High intelligence is common enough among executives. Imagination is far from rare. The level of knowledge tends to be high. But there seems to be little correlation between a man’s effectiveness and his intelligence, his imagination, or his knowledge. Brilliant men are often strikingly ineffectual; they fail to realize that the brilliant insight is not by itself achievement. They never have learned that insights become effectiveness only through hard systematic work. Conversely, in every organization there are some highly effective plodders. While others rush around in the frenzy and busyness which very bright people so often confuse with ‘creativity,’ the plodder puts one foot in front of the other and gets there first, like the tortoise in the old fable.” 

The One Minute Manager
Authors: Kenneth Blanchard and Spencer Johnson

Why it’s a must read: The One Minute Manager, along with The Greatest Salesman in the World, is the best of the “teach through parables” style of business book. The advice it offers is mostly common sense, but it’s laid out in such easily understood terms and actionable advice that it makes common sense into something that’s uncommonly valuable.

Best quote: “The managers who were interested in results often seemed to be labeled ‘autocratic,’ while the managers interested in people were often labeled ‘democratic.’ The young man thought each of these managers–the ‘tough’ autocrat and the ‘nice’ democrat–were only partially effective. ‘It’s like being half a manager,’ he thought. He returned home tired and discouraged. He might have given up his search long ago, but he had one great advantage. He knew exactly what he was looking for. ‘Effective managers,’ he thought, ‘manage themselves and the people they work with so that both the organization and the people profit from their presence.'” 

Dilbert and the Way of the Weasel
Subtitle: A Guide to Outwitting Your Boss, Your Coworkers, and the Other Pants-Wearing Ferrets in Your Life
Author: Scott Adams

Why it’s a must read: Adams’s earlier book, The Dilbert Principle, outlined the absurdity and inconsistency of the business world. This book goes deeper into management and decision making, explaining why everyone’s experience at work differs so greatly from the idealized picture that’s provided in books like The Effective Manager and The One Minute Manager. If you’ve got a sense of humor, this book will definitely make you laugh, but it will probably be the uncomfortable laugh resulting from seeing a bit too much of your own inner weasel.

Best quote: “There’s a gigantic gray area between good moral behavior and outright felonious activities. I call that the Weasel Zone* and it’s where most of life happens. (Note: *Sometimes known as Weaselville, Weaseltown, the Way of the Weasel, Weaselopolis, Weaselburg, and Redmond.)” 

The Age of Unreason
Author: Charles Handy

Why it’s a must read: Every book you’ve read about the digital age, disruptive innovation, massive change, etc., is based on this book. This was the first book to really nail the fact that what we now call the Mad Men era was disappearing and that we were about to slip into a crazy period where none of the old rules work and nothing makes much sense. It’s a quick read and some of his observations are dated, but it’s really amazing how much he got right and how much later business writers have stolen his ideas.

Best quote: “We are now entering an Age of Unreason, when the future, in so many areas, is there to be shaped by us and for us–a time when the only prediction that will hold true is that no predictions will hold true; a time, therefore, for bold imaginings in private life as well as public, for thinking the unlikely and doing the unreasonable.” 

The Art of War
Author: Sun Tzu

Why it’s a must read: This book is usually read as if it were a collection of fortune cookie proverbs. That misses the point, though, because this book is actually a philosophy of life that extends to every type of leadership. It’s one of those books that you can read 50 times and get something different with each successive reading. The edition that I’ve linked into the heading above is not just a beautiful work in the art of publishing but also contains the best commentary and notes, all of which can deepen your understanding.

Best quote: “Be extremely subtle, even to the point of formlessness. Be extremely mysterious, even to the point of soundlessness. Thereby you can be the director of the opponent’s fate.” 

Don’t Bring It to Work
Subtitle: Breaking the Family Patterns That Limit Success
Author: Sylvia Lafair

Why it’s a must read: If you’ve ever wondered why the people you work with behave in such strange ways, wonder no more. As this book clearly explains, whatever happened or is happening in their family is reflecting and repeating itself at work. What’s truly valuable about this book is that it identifies the personality types that cause problems and then explains exactly how to use and redirect the problematic behavior so that it serves the goals of the team.

Best quote: “Once you learn how people’s past family life and their work behaviors connect at a core level, you’ll know where performance problems originate and conflict starts. Then you’ll gain skills to do something about it. The reason most organizational programs abort is that they fail to deal with our life patterns, which are at the foundation of workplace anxiety, tension, and conflict.” 

The Prince
Author: Niccolo Machiavelli

Why it’s a must read: This is a book of bad advice. It was supposed to be “how-to” guide for leaders in Italy at a time when every city was fighting every other city and the entire region was full of mercenaries, inquisitors, and other unsavory types. Why do I include it? Simple. This book accurately predicts the decisions of a sociopath in a management role. As such, it’s perfect defense against predatory competitors and allows you to keep one step ahead.

Best quote: “And here comes in the question whether it is better to be loved rather than feared, or feared rather than loved. It might perhaps be answered that we should wish to be both; but since love and fear can hardly exist together, if we must choose between them, it is far safer to be feared than loved.” 

The 21 Irrefutable Laws of Leadership
Subtitle: Follow Them and People Will Follow You
Author: John C. Maxwell

Why it’s a must read: Sometimes it seems like everyone in the management consulting business has a list of principles, habits, laws, rules, and so forth that explain everything you really need to know. What’s funny about all those books, though, is that they’re all valid! Leadership is such a complicated phenomenon that it’s possible to describe it in hundreds of different ways. That being said, this book (of all the other books of this type) is the easiest to read, with techniques that are easy to apply. (Note: In this category, I went back and forth between this book and The 7 Habits of Highly Effective People. But 7 Habits gets a little preachy, so I finally settled on this book.)

Best quote: “Instinctively, successful people understand that focus is important to achievement. But leadership is very complex. During a break at a conference where I was teaching the 21 Laws, a young college student came up to me and said: ‘I know you are teaching 21 Laws of Leadership, but I want to get to the bottom line.’ With intensity, he raised his index finger and asked, ‘What is the one thing I need to know about leadership?’ Trying to match his intensity, I raised my index finger and answered, ‘The one thing you need to know about leadership is that there is more than one thing you need to know about leadership!'” 

How to Win Friends and Influence People
Author: Dale Carnegie

Why it’s a must read: The writing style is a bit corny and the anecdotes incredibly out-of-date, and yet it’s a well of wisdom that has yet to run dry. Everyone I’ve known who has read this book cover to cover (and made the effort to implement its lessons) has been successful, if not in business then in their personal life. This book has been a bestseller for decades and is likely to be a bestseller for decades to come. There’s so much in this book that for the quote, I just plucked out one that’s helped me in my interactions with colleagues and family members.

Best quote: “Criticism is futile because it puts a person on the defensive and usually makes him strive to justify himself. Criticism is dangerous, because it wounds a person’s precious pride, hurts his sense of importance, and arouses resentment.”