Elisabetta De Antoni observes that in the last decades of the past century, the dominant theory re-proposed an absolute faith in the stability of the private sector. Governments had to privilege their inter-temporal budget constraints, central banks had to pursue low inflation targets. Few years ago, economists and policy makers rejoiced at the great moderation, namely the decline in macroeconomic volatility since the mid-1980. Now, however, the real economy is overwhelmed by an unprecedented financial crisis. Something went wrong in the relationship between dominant theory and practice. This chapter offers a retrospective on the thought of three heterodox economists: Robert Clower, Axel Leijonhufvud and Hyman Minsky. What unites them are two key points, according to the author: first, the rejection of the ‘dogma of stability’; and second, the demonstration that, outside equilibrium, money and finance acquire an active role that can be seriously destabilizing.