ABSTRACT
In order to protect the following comments from a not unnatural misunderstanding, the author want to make it quite clear right away that he/she have no wish to advocate the historical approach to the phenomenon of business cycles at the expense, still less to the exclusion, of theoretical or statistical work upon it. The fact envisaged may be illustrated by every major crisis in history, but it will suffice to illustrate my meaning by the depression that broke in 1929. It is tempting to define the resulting relation between the two 'indispensables', the historical analysis and the dynamic model, by means of the concepts, Impulse and Propagation Problems. Nothing has been said so far as regards the nature of the historical information required. Also, it should not be forgotten, that there are many individual problems about business cycles which can only be solved on the basis of such understanding.
