Peter Drucker

Austrian-American management consultant and author who wrote 39 books and invented modern management as a discipline — creating concepts like management by objectives, the knowledge worker, decentralization, and the purpose of business as creating a customer — considered the most influential management thinker of the 20th century.

Invented modern management as a discipline — Drucker's central insights (the purpose of a business is to create a customer; management is a liberal art; knowledge workers cannot be managed like factory workers; decentralization makes large organizations functional) created the vocabulary and framework that every subsequent management thinker built on.