Here are excerpts from Zweig's article:
"From 1924 through 1946, while writing numerous books and overhauling the global monetary system, Keynes also found time to run the endowment fund of King's College at Cambridge.
Over that period, according to Messrs. Chambers and Dimson, Keynes outperformed the U.K. stock market by an average of eight percentage points annually, adjusted for risk.
Such great investors as Benjamin Graham, Peter Lynch, John Templeton and Warren Buffett beat the market by an annual average of three to 13 percentage points over their careers. Most of them, however, didn't have to cope with the Great Depression or World War II.
How did Keynes do it?
Flexibility, resilience and independence.
Keynes began as what we would today call a "macro" manager, relying on monetary and economic signals to rotate in and out of stocks, bonds and cash. He traded foreign currencies and commodities. As a director of the Bank of England, Keynes was privy to inside information about interest-rate changes, although there isn't evidence that he traded on it.
But Keynes wasn't a very good macro manager. He lagged behind the British stock market miserably until 1928, and he had 83% of his primary portfolio in stocks going into the fall of 1929.
"It's hard to time the markets," Mr. Chambers says. "Keynes struggled with it, and then he missed the 1929 crash—even with an unrivaled network of information sources."
So Keynes made a series of radical changes: He switched from being a "top down" asset allocator to a "bottom up" stock picker. He tilted sharply toward undervalued small and midsize companies.
Keynes also made titanic bets on industries he thought were cheap..."