Five people lean on a parapet at Pena, in Sintra, looking out over the forest toward the coast. Nobody faces the camera. You see the backs of heads, a shoulder, the angle of a jaw, and past them the whole Atlantic plain going hazy in the light. If that composition feels familiar before you can say why, it should. It is one of the oldest tricks in European landscape painting, and the poster trade ran on it for a hundred years.

The vintage travel poster market is old enough to have developed its own pathologies. What began as nostalgic accumulation in the 1970s — former railway employees, tourism board retirees, people who remembered the originals in context — has evolved into a structured secondary market with auction records, condition grading systems, and a small number of dealers who have spent decades building expertise the books don’t contain. Understanding what drives value in this market requires understanding both the history of the objects and the psychology of the people who want them.