Much has been learned about business cycles since 1913, when my first book on that problem was published. Economic theorists have been studying the phenomena with increasing energy and thoroughness--Albert Aftalion and Jean Lescure in France; Mentor Bouniatian and S. A. Pervushin in Russia; Gustav Cassel in Sweden; John Maurice Clark, William T. Foster, Waddill Catchings, Alvin H. Hansen, and Henry L. Moore in America; R. H. Hawtrey, John A. Hobson, A. C. Pigou, and Dennis H. Robertson in England; Emil Lederer, Joseph Schumpeter and Arthur Spiethoff in Germany, to name but a few. Economic statisticians have made rapid progress in analyzing time series--witness the accomplishment of Warren M. Persons and his many co-workers here and abroad. Most important of all in promise for the future, the leading commercial nations are learning to keep more adequate records of their economic activities. Of the extraordinary business fluctuations through which the world has been passing of late, we have fuller knowledge than of any earlier cycles.
For perhaps ten years my unwieldy quarto has been out of print. At least as long it has been out of date. Nor could it be brought abreast of current research by mere revision. It became plain that if I could add anything of value to the work in process it would be only by writing a new book. But single-handed, I could not manage the wealth of new materials, or apply the improved methods of statistical analysis. From this quandary I was rescued by the National Bureau of Economic Research, which offered to collect and analyze the data I needed, and to supply the gaps in my equipment.
Despite the National Bureau's efficient aid, my resurvey of the field is taking more time than the first survey took. This work has been my chief concern since 1923, yet only one volume is ready for publication. It deals, as the sub-title indicates, with "The Problem and its Setting." A second volume on "The Rhythm of Business Activity" will follow as soon as I can finish it.
The present treatise resembles its forerunner in general plan. But the statistical data prove so extensive that they must be pub-