In a post-war exhibition, a man encounters a propaganda leaflet container and compares it disparagingly to an explosive bomb. Another visitor explains the importance of propaganda and outlines the factors which influence public opinion: daily newspapers, magazines and digests, library books, etc. Examples are shown of how the printed word has great power for good or evil, and how it can quickly be disseminated through daily conversations, radio and cinema.

Public opinion is mobilised by groups of like-minded people joining together - for example, the NSPCC, trade unions and so on. Many important reforms came about as a result of successful agigators - Wilberforce, Nightingale, Fry, etc. Legislation results from public opinion being brought to bear on parliament: in order to get your voice heard, you need to team up with like-minded people until it becomes loud enough.