
Penguin paperbacks date back to 1935, but really reached their height of popularity in the 50s and 60s.
Under the guidance of Germano Facetti, Penguin produced book covers based on a common typography and design. Genres were indicated by the colour on the sleeve: Orange for fiction, green for thrillers, light blue for factual and dark blue for biography.
Pelicans and Puffins both followed.