The concept of community can take various forms. In a basic sense, it embodies the idea of sharing something, such as values, goals or interests. Community can also be a network of social ties, reinforced by a shared vision of self or identity. Finally, it can be defined simply as the neighbourhood, city or geographical area where one lives. Throughout Canada’s history, many men and women have advocated on behalf of their community, whether a city, province, ethnic group, religious community or community of ideas. To celebrate its 30th anniversary, the Encyclopedia drew up a list of 30 leaders (in the broad sense of the term) who have emerged from the diverse communities that make Canada the vibrant place it is.