In 1989, Stephen R. Covey penned The 7 Habits of Highly Effective People (public library), a book that went on to sell millions of copies worldwide and defined a new genre bridging self-improvement, business management, and personal productivity. This week, Covey passed away at the age of 79. Here’s a look back at his legacy with some of the keenest insights from his beloved bestseller.

Habit is the intersection of knowledge (what to do), skill (how to do), and desire (want to do).

Sow a thought, reap an action; sow an action, reap a habit; sow a habit, reap a character; sow a character, reap a destiny.*

People can’t live with change if there’s not a changeless core inside them.

Until a person can say deeply and honestly, ‘I am what I am today because of the choices I made yesterday,’ that person cannot say, ‘I choose otherwise.’

To learn and not to do is really not to learn. To know and not to do is really not to know.

It is one thing to make a mistake, and quite another thing not to admit it. People will forgive mistakes, because mistakes are usually of the mind, mistakes of judgment. But people will not easily forgive the mistakes of the heart, the ill intention, the bad motives, the prideful justifying cover-up of the first mistake.

Admission of ignorance is often the first step in our education.

Our behavior is a function of our decisions, not our conditions.

The ability to subordinate an impulse to a value is the essence of the proactive person.

How you treat the one reveals how you regard the many, because everyone is ultimately a one.

There’s no better way to inform and expand your mind on a regular basis than to get into the habit of reading good literature.

And, of course, the meat of The 7 Habits of Highly Effective People:

Habit 1: Be Proactive
Habit 2: Begin with the End in Mind
Habit 3: Put First Things First
Habit 4: Think Win/Win
Habit 5: Seek First to Understand, Then to Be Understood
Habit 6: Synergize
Habit 7: Sharpen the Saw

* Covey is, of course, paraphrasing Gandhi.