da Veiga-Simões, A. Keywords: Economic crisis | Intervention | Economy | Mots clefs: Crise économique | Intervention | Economie | ABSTRACT In this course, A. Da Veiga-Simões focuses on economic crises. After having presented the inanity of the theories concerning them, he presents its history, its effects and considers the possibilities of intervening in order to prevent them or cure them. He concludes that in times of extreme depression, we should involve foreign forces in economy. Dans ce cours, A. Da Veiga-Simões s'intéresse aux crises économiques. Après avoir présen…