¹ Readers who are not interested in the problems of scientific methodology, but only in the concrete results of our studies, can dispense with the reading of the first part of what follows.

² Pierre Vendryès, Vie et Probabilité (Albin Michel).

³ Von Neuman and Morgenstern, Theory of Games (Princeton University Press).

⁴ I do not say, ‘we shall content ourselves with …', because to hope for more in economic matters would be to fail to recognise objective realities and to pursue phantoms.

⁵ It is obvious that we can give only a short sketch of our method here. This method, however, does not assume its full value unless it is applied to the concrete, detailed study of real situations. For this, we would refer our readers to our principal works as enumerated on p. 114.

⁶ It goes without saying that we are carrying this calculation out here only in very rough terms. To bring it closer to reality, we would have to introduce the figure of over-all popu lation, because its proportion has varied in relation to the active population. But this does not change the order of magnitude of the figures.

⁷ Each class may be characterised by a typical product, which serves as a point of reference and as an example. It is for this reason that the method whose introduction into economic science we are recommending, is sometimes designated in other sciences as ‘typology'.

⁸ Taken from Le grand espoir du XXe siècle, p. 88.

⁹ Tertiary activity is an abbreviated expression for: activity devoted to the elaboration ‘of a product or a service of the tertiary type.