Drucker’s views on strategy were quite different from those taught by others. He did not believe in "portfolio management" or quantitative methods for strategy development. Drucker felt that every situation had to be approached individually and with common sense based on history. This is probably one reason that Drucker, although a self-proclaimed "non historian," used historical examples to illustrate his concepts. And though the word "strategy" comes from the Greek word, "strategos," he did not believe that "business is war" or that one should look at business as an act of warfare.