The concept of desire is the key to understanding the relation between economics and psychoanalysis, that is, between social and psychic investment, or between productive and libidinal economies. Today, the system organising the relation between these two economies is less a matter of biopower than of 'psychopower', technologies and industries developed in order to control the behaviour of consumers. But this system interferes with the intergenerational circuits on which desire has hitherto always been based. Consequently, the system is now encountering certain limits, threatening the collapse of the system itself, and requiring a new economic understanding, itself dependent on a new theoretical foundation for understanding desire in general.