The first word in the title-advertising-is not difficult to understand. We are all familiar with the colourful, amusing and appealing posters that adorn the walls of our streets and railway stations. We cannot fail to notice, and sometimes read, the advertisements in our newspapers and magazines. They are far too numerous to be ignored, and far too irresistible not to make some mark on our thoughts and actions. Again, we cannot fail to turn our gaze toward those ingenious signs, many of them animated, that enliven the night sky of our cities with their scintillating glow. We think, too, of the great exhibitions and trade fairs, with their array of cleverly designed booths presenting the latest products, devices and inventions in every kind of merchandise. Modern advertising presents its message in a variety of forms; attracting, informing, reminding, suggesting and impelling us many times during the course of any single day. To what extent advertising influences our tastes, preferences and purchases may be gauged by the number of things we buy directly or indirectly as the result of reading advertisements, either at the point of sale, when we enter a store, or at some time previously.