This article by Richard R. Nelson, published in the Journal of Economic Literature, explores the evolution of evolutionary thinking in economics, particularly in the context of socio-economic change. Nelson assesses the state-of-the-art in fields such as technological change, innovation-driven growth, and cultural and institutional evolution. He highlights the tension between equilibrium theories, which are elegant and mathematically tractable, and evolutionary theories, which often rely on biological metaphors and complex, dynamic processes. Nelson argues that while equilibrium theories are useful for describing and explaining economic phenomena, they often fail to capture the dynamic and complex nature of economic change. He discusses the recent development of formal evolutionary theories in economics, influenced by evolutionary biology and sociobiology, and notes that these theories have been applied to various aspects of economic change, including science, technology, business organization, and law. Nelson also critiques the limitations of these theories, particularly their failure to account for the path dependency and continuous disequilibrium in economic processes. The article concludes with a reflection on the current state of evolutionary theorizing in economics and proposes criteria for evaluating the strengths and weaknesses of evolutionary models compared to neoclassical theories.This article by Richard R. Nelson, published in the Journal of Economic Literature, explores the evolution of evolutionary thinking in economics, particularly in the context of socio-economic change. Nelson assesses the state-of-the-art in fields such as technological change, innovation-driven growth, and cultural and institutional evolution. He highlights the tension between equilibrium theories, which are elegant and mathematically tractable, and evolutionary theories, which often rely on biological metaphors and complex, dynamic processes. Nelson argues that while equilibrium theories are useful for describing and explaining economic phenomena, they often fail to capture the dynamic and complex nature of economic change. He discusses the recent development of formal evolutionary theories in economics, influenced by evolutionary biology and sociobiology, and notes that these theories have been applied to various aspects of economic change, including science, technology, business organization, and law. Nelson also critiques the limitations of these theories, particularly their failure to account for the path dependency and continuous disequilibrium in economic processes. The article concludes with a reflection on the current state of evolutionary theorizing in economics and proposes criteria for evaluating the strengths and weaknesses of evolutionary models compared to neoclassical theories.