The Crash of 1929, as seen by Paul Cabot in 1930

From the State Street Research and Management 1930 Annual Report. (as quoted in Michael Yogg's Passion for Reality):

"All common stock investors lost, irrespective of the care with which their investments were made or supervised. No amount of research work could have prevented such losses unless it was decided that no equities should be used.

"One has only to review the utterances of leading economists, research organizations, and businessmen during the past eighteen months to discover how small is the amount of real knowledge and understanding concerning problems of major economic importance. In spite of all the research work that has been done on such prolems, it appears that common sense will remain the intelligent investor's most reliable and useful asset." (p. 55)

And yet, common sense is all too uncommon.