In most newspapers and magazines, the booklet-like format is accomplished by folding large sheets of paper in half.
Notice how, in this example, the two middle pages, 8 and 9, will appear next to each other on the back of sheet D. This creates a double truck.
For example, newspaper often use a double truck to display large illustrations, graphics, maps or photo collages, often in full color.
Often double trucks are saved for special reports or in-depth graphical elements.
The name "double truck" comes from the days when the heavy forms for newspaper pages (the metal version of each page), largely filled with lead type, were rolled around the composing room floor on heavy carts called trucks.