Our modern society and competitive economy depend on a strong digital foundation and, in turn, on sustained research and innovation in computer systems and networks (CompSys). With this manifesto, we draw attention to CompSys as a vital part of ICT. Among ICT technologies, CompSys covers all the hardware and all the operational software layers that enable applications; only application-specific details, and often only application-specific algorithms, are not part of CompSys. Each of the Top Sectors of the Dutch Economy, each route in the National Research Agenda, and each of the UN Sustainable Development Goals pose challenges that cannot be addressed without groundbreaking CompSys advances. Looking at the 2030-2035 horizon, important new applications will emerge only when enabled by CompSys developments. Triggered by the COVID-19 pandemic, millions moved abruptly online, raising infrastructure scalability and data sovereignty issues; but governments processing social data and responsible social networks ... : Position paper: 7 foundational research themes in computer science and networking research, 4 advances with outstanding impact on society, 10 recommendations, 50 pages. Co-signatories from (alphabetical order): ASTRON, CWI, Gaia-X NL, NIKHEF, RU Groningen, SIDN Labs, Solvinity, SURF, TNO, TU/e, TU Delft, UvA, U. Leiden, U. Twente, VU Amsterdam ...