Introduction.- Towards a Sustainable European Research Infrastructures Ecosystem.- Economics of Science in the Time of Data Economy and Gigabit Society.- The SKA Approach to Sustainable Research.- The European Spallation Source: Designing a Sustainable Research Infrastructure for Europe.- Optimising the Benefits from Research Institutes.- Rethinking the Socio-economic Value of Big Science: Lessons from the FCC Study.- Socio-Economic Impact Assessments of ESA Programmes: A Brief Overview.- Designing a Socio-Economic Impact Framework for Research Infrastructures: Preliminary Lessons from the RI-PATHS Project.- Findings from the LHC/HL-LHC Programme.- Designing a Research Infrastructure with Impact in Mind.- Leveraging the Economic Potential of FCC's Technologies and Processes.- How to Value Public Science Employing Social Big Data?.- R&D, Innovative Collaborations and the Role of Public Policies.- Large-Scale Investment in Science: Economic Impact and Social Justice.- Investing in Fundamental Research: For Whom? A Philosopher's Perspective.- Investing in Fundamental Research: Evaluation of the Benefits that the UK Has Derived from CERN.- Fundamental Science Drives Innovation.- Epilogue: Productive Collisions-Blue-Sky Science and Today's Innovations.