The use of "participatory research" and "participation" to promote the empowerment of the poor and marginalised began in the 1970s and gained momentum in the early 1980s. The approach builds on the "learning for change" paradigm in which everyday experience is the basis for developing agency, and committing to and taking action to create change, both individually and collectively. The paradigm has been used over decades, and in several contexts (e.g. women's literacy and political leadership, work health and safety, access to and control over natural resources, prevention of sexual harassment and violence against women, social accountability and participatory monitoring, access to basic services, and climate adaptation and resilience). In this research note, some of these contexts -- work health and safety, women's political leadership, the urban poor and gender-based violence -- are used as practical exemplars of work conducted by the non-profit research and training organisation Participatory Research in Asia (PRIA) to support poor, excluded and marginalised communities. The experiences shared in this research note bear witness to the power of popular knowledge and the inclusion of marginalised voices for transformatory, people-centric development.