Explore decision-making in uncertain environments through Professor Eric Kerrigan's inaugural lecture at Imperial College London. Delve into the importance of measurement in reducing uncertainty and making informed choices across various fields. Gain insights into aerodynamics, electrical engineering, and energy systems as examples of complex decision-making scenarios. Learn about equations, constraints, and optimization techniques used to tackle real-world problems. Discover the principles of control and optimization, including approximate optimization methods. This 1-hour 9-minute talk provides a comprehensive overview of how to approach decision-making when faced with known unknowns, offering valuable knowledge for professionals and students in engineering, science, and related disciplines.