The document defines the National Innovation System (NIS) as a network of institutions that drive technology flow and innovation on a national level. It outlines the importance of NIS in enhancing a country's technological capacity and innovative performance, and describes its application through the development of indicators, analysis of relationships among key actors, and understanding sectoral innovation systems such as the Thai automotive industry. Key actors include government bodies, private enterprises, universities, and research institutions, who collectively contribute to the production, diffusion, and utilization of innovations.