Matthew Hays's book review of Challenge for Change: Activist Documentary at the NFB of Canada, explains Canada's considerable influence on the evolution of documentary film making. This book provides an epic examination of this movement called Challenge for Change/Societe Nouvelle series (1967-80), which aimed to marry new doc filmmaking techinques with progressive politics. It also offers up some excellent assessments of the films in focus, including Brenda Longfellow's The Things I Cannot Change, which has long been held up as an example of exploitative filmmaking.