ABSTRACT
Every economist knows Professor Mitchell's great book of 1913 and also the present instalment of the new monumental work. It is indeed obvious that in dealing with business cycles we are dealing with all the most fundamental elements of the economic life of capitalist society, and are sure to meet practically all our great problems on our way. Professor Mitchell, as he has told us somewhere, is no friend to systematic treatises, which most of us will probably agree to be in some respects necessary evils. There is undoubtedly a difference in aim and character. Marshall's fame and influence rest on his mastership in constructing tools of analysis, on his having built, out of the material of the theoretic ideas of his time, an engine of analysis. Professor Mitchell, in dealing with the duration of cycles, finds, for instance, many more of them than his predecessors used to.
