Professor Siegel emphatically rejected the warnings of extreme bears like Robert Prechter, the Elliott Wave theorist, whose predictions of an epochal market collapse were discussed in this column two weeks ago. To the contrary, he said, the future is bright, and the possibility of a double-dip recession “minimal.”

He pointed to significant economic problems — including the European debt crisis, the possibility that the Chinese juggernaut will stumble, and persistent high unemployment in the United States. But he said that here, at least, the Federal Reserve, under the former Princeton economics professor Ben S. Bernanke, would do what it took to maintain financial stability.

As for the stock market, Professor Siegel said, “there is every reason to believe that mean reversion will continue” — that is, that despite sometimes excruciating declines, the market over the long run will produce average real returns of more than 6 percent annually. “The shocks of the recent past shouldn’t alter investors’ belief in the future,” he said.

The spine of “Stocks for the Long Run” was a study of the United States market going back to 1802, using data from several sources. Over that period, he found that the stock market outperformed every other asset class. In stretches as long as 20 years — including the last 10 and 20 years, according to data provided to Sunday Business by Morningstar — long-term government bonds have sometimes outperformed stocks. But as holding periods lengthened, he found, the stock market has almost always pulled ahead. Other studies have found similar results in other countries.

Emphasizing dividend-paying value stocks and investing globally will bolster your chances, he said.

What’s more, when stocks are cheaper than average, as measured by the price-to-earnings ratio, positive returns became more probable in subsequent years. That is very encouraging for the current market, in which earnings have been rising despite widespread skepticism, keeping the P/E of the Standard & Poor’s 500-stock index at a modest level. Based on consensus estimates, it stands at 13. That compares with an annual average of 15.2 since 1945, he said.