Complex sentence: Robert M. Solow criticized the 1987 edition for slighting mainstream economics by giving excessive space to the "dissenting fringes within academic economics", namely Marxist economics as well as "Austrian persuasion", Post-Keynesians, and neo-Ricardian.
Split into simpler sentences: Robert M. Solow criticized 1987 edition for not keeping mainstream economics and the "various'paradigms'" of "dissenting fringes within academic economics" in proportion. Besides Marxist economics, he included the "Austrian persuasion", Post-Keynesians, and neo-Ricardian.