A musician spends years honing his craft. He writes world-class songs and performs them in a manner that moves his listeners to tears. He records a demo tape and sends it to record labels. He gets a contract and becomes rich, famous and adored. The lesson: demo tapes are the secret of becoming a famous musician. Wait, you say, the demo tape was just a tool, just his way of conveying his talent. It’s his ability as a musician that got him the contract and made him famous. You’re right, of course. He could have become just as famous if