In July 1971, Michael Edesess, having received a Ph.D. in mathematics, started his first job, performingtheoretical work on the stock market at a major brokerage firm. Within months he realized something was askew. The academic findings were clear and undeniable, but the firm—and the whole industry—paid no real attention to them.Theories and evidence both showed that professional investors could not beat market averages. A typicalstudy in The Journal of Finance concluded: “The evidence on mutual fund performance discussed above indicates not only that … mutual funds were on average not able to predict security prices well enough to outperform a buy the-market-and-hold policy, but also that there is very little evidence that any individual fund was able to do significantly better than that which we expected from mere random chance.”Professional investors couldn’t even predict stock prices better than the nearest taxicab driver. Yet the entirebusiness was based on the falsehood that they could.It was as if theoretical physicists knew the laws of thermodynamics but, nevertheless, the business ofengineers was selling plans for perpetual motion machines.The Big Investment Lie is that an investor will gain by hiring professional advisors and managers to beat themarket. Widespread acceptance of this lie allows an entire industry to prosper lavishly. But an investor will almost surely lose—more than they imagine—by hiring professional help.Over a long career Edesess observed, often aghast, often as a deeply-placed insider, while the pitch for theLie became more elaborate, and outlandish fees for a worthless service actually increased.In The Big Investment Lie, Edesess shows how to break free from this pervasive falsehood. By following hisTen New Commandments for Smart Investing, investors will maximize their long-run wealth and achieve theirbest possible financial future.