The 7 Habits of Highly Effective People — Covey (1989)

The 7 Habits has sold 40 million copies, the highest total on this list, outperforming 'How to Win Friends' by 10 million units. Stephen Covey's framework — from dependence to interdependence — and the Eisenhower Matrix, which prioritizes tasks by urgency and importance, have been adopted by 80% of Fortune 500 companies. A 2022 survey found that readers applying its principles report a 35% increase in personal effectiveness. It is two decades older than 'Atomic Habits' yet remains 15% more widely cited in business curricula.