Donald Thomas 'Don' Valentine (June 26, 1932 – October 25, 2019) was an American venture capitalist renowned for his pivotal role in shaping Silicon Valley's investment landscape. Born in New York and educated in the state, he served briefly in the military before moving to California, where he built a career in the semiconductor industry at companies like Fairchild Semiconductor and National Semiconductor. This experience honed his expertise in technology markets and provided the foundation for his later success in venture capital. In 1972, Valentine founded Sequoia Capital, a pioneering venture capital firm that became one of the first dedicated to technology startups in Silicon Valley. Under his leadership, Sequoia became a powerhouse, providing early-stage funding to iconic companies such as Apple, Cisco Systems, Oracle, and later investments in Google, YouTube, NVIDIA, Airbnb, and WhatsApp. Known for his blunt, Socratic investment style, Valentine prioritized large markets, early inflection points, and humble, capable founders. He mentored successors like Doug Leone, who took over leadership at Sequoia, ensuring the firm's enduring influence in the tech sector. Valentine's contributions extended beyond investments; he was instrumental in establishing venture capital as a critical engine for innovation in the United States, leaving a legacy as a major figure in Silicon Valley's history whose approach helped transform Sequoia into an influential firm backing numerous tech giants that defined the digital age.