"What sex is to the biology classroom, stocks and investment riskiness is to the sophomore economics lecture hall. That chapter on personal finance, put there to keep hard-boiled MIT electrical engineers awake, helped make introductory economics the largest elective course at hundreds of colleges. My great predecessors—John Stuart Mill, Alfred Marshall, Frank Taussig and Irving Fisher—were writing for their times. I was writing for the last half of the 20th century-an epoch that surpassed even my youthful optimism. Those classic authors had dealt with essentially pure capitalism. I had to grapple with the tradeoffs and opportunities inherent in the mixed economy, a social pattern that by now spreads across the continents of the Americas, Europe, Asia, and Africa."