Every so often Canon brings out something that's just plain weird (e.g. the Photura); somethingthat doesn't fit with anything else they are doing at the time, and the EXEE is a perfect example. In the late 60s Canon was building up its F-series cameras with a run up to its top-of-the-line professional F-1. Meanwhile it had the serious-amateur market with the FT and its less expensive little brother, the TL. They took standard FL lenses. It was the way things were going.
But Canon brought out the EXEE, which was a throwback to an earlier time. It was a solid body that looked like all the other Canon F bodies, but it had a half-lens permanently mounted onto it. The idea was that user would have three interchangable halfs that could be attached, offering a standard 50mm lens, a 95mm lens, or a 125mm lens.
It was a ridiculous idea since a buyer could pick up a comparable TLb and mount any FD lens in Canon's arsenal, including longer teles and wide angles (something the EXEE didn't offer at all). A popular combo for amateurs ended up being the three lens 28mm, 50mm, and 135mm set—the trio for this camera doesn't even come close.
This camera was also sold as the Bell & Howell Auto 35 Reflex. B&H had imported Canon cameras for most of the 1960s, but when they parted company, B&H got a couple of Canon cameras branded solely under the B&H name. The lenses, however, retained the Canon name and fit either camera.
One other camera takes this same lens system, the Canon EX Auto (I don't yet have one).
The Canon is a swap-meet find, and I got two accessory lenses to go with it, and they're both the 125mm. I may have the 90mm but haven't been able to locate it.
For more information: Canon Camera Museum