I'm no expert on these things, but it looks to me like this is a camera for photographing artwork in order to make printing plates. Photos & text would be assembled on a large sheet which would then be photographed by this camera. In some cases, the back end of the camera would actually be in a darkroom, where the camera operator/plate maker would develop the exposure, usually enlarge it, and then make a printing plate from it. The camera in the photo looks to have a mirror, at 45°, in front of the lens. This would be so a photograph could be made of artwork that was on a table, parallel to the ground.
I can't tell how large your camera actually is, but they would normally be quite large, since the bigger the initial exposure, the sharper the enlargements would be.
The question of value is a tough one, because although it looks to be a high-quality piece of equipment, and likely still operational, its sheer size makes it difficult to sell. You never know though - you could put it up on eBay and see if there are any (local) takers. A commercial photographer could certainly use such a camera in their studio. A printing company may want it as well, for display in their lobby perhaps. Sometimes the value of an item is simply what someone is willing to pay for it.
I hope this helps you.