Having put up a post about the principles of a shift lens, using the manual to my ancient MPP large format camera, I thought it might be useful to show the camera itself. In this photo, the raised lens is clearly visible. This alters the relation of the film and lens planes, and enables perspectives to be corrected.

Here's its big brother, a monorail version (made by Toyo, about 30 years ago). The 5x4 format is identical but it is much more flexible when working with ultrawide lenses. On the downside, it's unwieldy and needs to be carried around on a trolley.
Toyo 5x4 monorail camera