Management itself
Essentially invented management as a subject, and most of what came after is a footnote to him.
Photograph: Jeff McNeill · CC BY-SA 2.0 · Wikimedia Commons
Drucker wrote for six decades and framed most of the questions the rest of this list is still answering. He argued that management was a genuine discipline that could be studied and taught, at a time when it was assumed to be either common sense or the exercise of authority.
He introduced or popularised management by objectives, the idea of the knowledge worker, decentralisation, and the argument that a business exists to create a customer — not to make a profit, which he treated as a condition of survival rather than a purpose.
The writing is plain and the questions are the durable ones: what is our business, who is the customer, what does the customer value, what are our results. Most strategy work is those four questions with more spreadsheets.
Profit is the test of whether you did it well and the cost of staying in business — not the objective. It reorients every planning conversation away from what you want and towards what someone will pay for.
Widely attributed to him and widely abused. The useful version is the warning: measure the wrong thing and you will get more of the wrong thing, done efficiently.
His most under-used idea. Regularly ask of every product, process and activity: if we were not already doing this, would we start it now? If not, stop. Businesses accumulate activity and almost never prune it.
These links go to their own work. We summarise and point — we do not republish it.
Anyone managing anyone, and anyone who wants the original version of ideas they have met second-hand.
Written for large organisations in a different era. The examples are dated even where the thinking is not.