This is one of those rare books which, if only they are received with the serious attention that they deserve, sometimes succeed in forcing an entirely new orientation in the field of scientific endeavour with which they deal. The book would deserve the closest attention, even if its specific arguments were found to be either unsound or of little permanent value for further research along positive lines, by virtue of the vision of its conception, the saneness with which it sets limits to the discussion, and the boldness with which it states its conclusions. It required an imaginative vision to pull one's self consciously away from the details both of present methods of ‘business forecasting’ and of the ‘cycle theories’ which, consciously or unconsciously, lie at the base of those methods, in order to examine the methodological assumptions common to all methods and theories. It required a saving sense of balance to prevent the inevitably abstract and formal nature of the treatment from leading to fruitless juggling with metaphysical subtleties of doubtful relevance. It required courage of high order to issue a challenge, couched in the most uncompromising terms, to the vested interests represented by those ‘Institutes’, commercial and ‘scientific’, which are at this moment devoting a huge expenditure, in time and effort, to the study of business forecasting.