For humanity and the environment to advance favorably, the best knowledge from each of the many subdisciplines within environmental science needs to be accessible and understandable by diverse readerships. Scientific advances published in peer-reviewed journals are meaningful only to those in the disciplinary niches. To serve greater societal needs, journal contents need to be synthesized by topic experts who clarify the importance and relevance within a broader context and convert this specialized knowledge into book form. However, because books on scientific topics in the preserve of the commercial publishing industry are unprofitable, they are rare. The Groundwater Project as a non-profit alternative offers a successful case study. It began publishing books online in 2020 for free downloading in many languages. Sixty-four original and 29 preserved books about groundwater science and related topics are now on the website with hundreds more coming along with self-learning materials. Created by volunteer topic experts in 32 countries, the books are focused on groundwater and how it connects to all parts of the water cycle, to ecological systems and society at large. This project serves as a model for democratizing actionable knowledge. Similar undertakings by other environmental domains would be a path to holistic understanding of the planet’s environment.