"Back in the 1980s, stock picking gurus such as Peter Lynch at Fidelity offered small investors a strikingly simple mantra: 'Invest in what you know,' writes Mitch Tuchman in an opinion piece for MarketWatch entitled "John Bogle's enduring wisdom and the trouble with mutual funds." "The idea was intuitive and highly attractive for a number of reasons. Essentially, if you noticed a small coffee chain with a line out the door, you bought that stock. If you worked in the aerospace industry, all the more reason to buy stock in your own firm." Read the original story from MarketWatch.