Marketing is your strategy for allocating resources (time and money) in order to achieve your objectives (a fair profit for supplying a good product or service)
Yet the most brilliant strategy won't help you earn a profit or achieve your wildest dreams if it isn't built around your potential customers. A strategy that isn't based on customers is rather like a man who knows a thousand ways to make love to a woman, but doesn't know any women. Great in theory but unrewarding in practice.