The monograph presents interdisciplinary research on social innovation, its essence and impact on sustainable development of society, its promoting and hindering factors and the ways how the obstacles are overcome. It analyses the stakeholders and their input in social innovation processes, considering also the scenarios of the development of social innovation in Latvia and the cases of best social innovation practices from Latvia and other European countries. The monograph provides also the analysis of the new concept of the indices of financial, informative and organizational involvement of stakeholders in social innovation processes with the research and calculation methodology elaborated by the research team. There is also the analysis of the sources of financing so far not used in Latvia for the implementation of social innovation. The work is intended for social innovation researchers, practitioners, social entrepreneurs, policy makers, heads of municipalities, educators and heads of educational institutions, students and all other individuals interested in social innovation and its promotion issues.