Knowledge-based capital (KBC) results from business investment in non-physical assets such as R&D, data, software, patents, new business models, organizational processes, firm-specific skills and designs. This publication brings together the results of a two-year programme of work at the OECD on New Sources of Growth and the role of Knowledge-based Capital (NSG-KBC). This work shows that business investment in KBC is a key to future productivity growth and living standards. In many countries, business investment in KBC has increased faster than - and in some countries significantly exceeds - investment in physical capital (like machinery). To promote long-term growth and the jobs of tomorrow, governments must ensure that framework conditions, institutions and policies facilitate business investment in KBC. Emerging economies are also making concerted efforts to help their businesses accumulate KBC. This book sets out policy analyses and recommendations in the fields of: innovation; taxation; entrepreneurship and business development; corporate reporting; big data; competition and measurement.