This book has been written as an introductory economics textbook for first or second year students, but it is also intended to be used on occasions as a textbook for courses on the principles of economics for third or fourth year students, and as a supplementary reader for private study by MSc students. Furthermore, at the risk of setting my hopes too high, I hope it will also be of interest to fellow economists.

The content of this book does, in fact, reproduce the content of the lectures which I have been giving to first year students at the LSE for several years now. Many of these students come to us having already studied ‘A’ Level economics in the sixth form, and the proportion of our students who have done this has recently been showing a marked increase. It is therefore desirable to present to them lectures with a higher-level content than ‘A’ level economics – often P. A. Samuelson's Economics and R. G. Lipsey's An Introduction to Positive Economics, for example – or at least lectures which do not just repeat the content of such works. This book marks my supply in response to this sort of demand.

The approach of this book differs to a considerable degree from standard economics. If one really wishes to study economics at the present time one has to pay assiduous attention to consumer theory and the theory of the firm, dependent on the concepts of the marginal rate of substitution and marginal productivity respectively.