The chapter discusses the microeconomic aspects of technology adoption, focusing on how poorer countries can catch up with richer ones through technological diffusion. It highlights the importance of understanding the determinants of technology adoption, particularly in agriculture, where most of the poor work. The authors review recent studies that examine various technologies, such as new seeds, fertilizers, and improved health technologies, and their adoption rates. They emphasize the need to understand the constraints on adoption and input allocation, as underutilization of existing technologies is common in poor economies. The chapter also delves into the measurement issues of returns to technology adoption, noting that accurate measurement is crucial for assessing the profitability of new technologies. It discusses the challenges in measuring outcomes, especially when the technology improves utility rather than profitability. The authors present a model of optimal input use and the returns to inputs, highlighting the role of heterogeneity and imperfect markets in inferring returns. Additionally, the chapter explores the concept of learning in technology adoption, both individually and through social learning. It examines how farmers learn about the returns to new technologies and how this learning affects their adoption decisions. The authors discuss the implications of learning for the diffusion of new technologies, including the potential for free-riding behavior and the rapid spread of information among larger farmers. Overall, the chapter provides a comprehensive overview of the microeconomic factors influencing technology adoption, emphasizing the need for further research to better understand the dynamics of technological diffusion in low-income countries.The chapter discusses the microeconomic aspects of technology adoption, focusing on how poorer countries can catch up with richer ones through technological diffusion. It highlights the importance of understanding the determinants of technology adoption, particularly in agriculture, where most of the poor work. The authors review recent studies that examine various technologies, such as new seeds, fertilizers, and improved health technologies, and their adoption rates. They emphasize the need to understand the constraints on adoption and input allocation, as underutilization of existing technologies is common in poor economies. The chapter also delves into the measurement issues of returns to technology adoption, noting that accurate measurement is crucial for assessing the profitability of new technologies. It discusses the challenges in measuring outcomes, especially when the technology improves utility rather than profitability. The authors present a model of optimal input use and the returns to inputs, highlighting the role of heterogeneity and imperfect markets in inferring returns. Additionally, the chapter explores the concept of learning in technology adoption, both individually and through social learning. It examines how farmers learn about the returns to new technologies and how this learning affects their adoption decisions. The authors discuss the implications of learning for the diffusion of new technologies, including the potential for free-riding behavior and the rapid spread of information among larger farmers. Overall, the chapter provides a comprehensive overview of the microeconomic factors influencing technology adoption, emphasizing the need for further research to better understand the dynamics of technological diffusion in low-income countries.