This is the older brother of my Zenit EM, a Russian SLR. Alfred's Camera Page has a really nice write-up on it, so I'm not going to duplicate much of it here. I found this guy at an "antique" mall for $13, which is a little less than it's worth IMO. It works and it's got a Carl Zeiss Tessar on it (as opposed to Russian optics), so I grabbed it.
They made this thing from 1965 to 1982, which is a very long run for a modern camera. It has (like my EM) a screw-mount lens, but The E model uses their own version of the 39mm screw mount, which is close to but not quite compatible with the standard M39 Lecia mount. They later changed over to the M42 Pentax/Praktica mount in 1967, but mine is the 39. This makes yet another 39mm screw-mount camera that I have that won't take standard M39 lenses (e.g., my Braun Super Paxette). Very frustrating.
Russian cameras are technologically backward, but they tend to be hardy. Even the selenium meter still works on this beast, though I haven't checked it for accuracy. But the price you pay is a non-automatic lens, no TTL metering, a very limited range of shutter speeds, and no rapid-return mirror (you have to wind the film/cock the shutter to also drop the mirror back down).
Camera manual: Orphan Cameras.com