After a 60-year career marked by incalculable contributions to the study of management, Peter F. Drucker passed away last November at the age of 95. Drucker, hailed by many as the father of modern management, wrote nearly 40 books and spawned management revolutions in top organizations like General Electric and the American Red Cross.

Remembered as much for his plain speech as for his prolific output, Drucker is widely considered to be the greatest management thinker and writer of all time. The Claremont University professor famously influenced towering leaders including Jack Welch, Winston Churchill, and mega-church luminary Bill Hybels, and Drucker-developed concepts like customer-focus, employee empowerment, and innovation are now considered foundational to the successful management of organizations.

Whether touting the value of decentralization or developing his management-by-objectives theory, Drucker conveyed ideas that resonated with top brass and everyday managers alike. At the heart of his writing is the belief that people are the most important resource to a company, and that the main function of effective managers, therefore, is to train and motivate workers and give them the freedom to perform their jobs. Drucker's thesis about work and motivation--that if workers are allowed to participate in decisions, they not only become happier and more productive, but they also provide valuable insights to the organization--is widely accepted today.