Paul Mattick Jr. 
Economic Crisis and Crisis Theory [PDF ebook] 

Keynesian economics claimed to have overcome the problem of economic depressions. However, as Mattick argues that crises are inherent within capitalism and that neither the market nor Keynesianism can stop "the steady deterioration of the economy". Written in 1974, Economic Crisis and Crisis Theory is one of Mattick’s most valuable contributions to the Marxist critique of political economy and radical theory in general.