Minolta professional SLR camera, it was known as the XK in North America and other locations such as Asia and Europe as XM or X-1.  The camera was built in the early 70's when Minolta was still pursuing the professional market against Nikon F-2, Canon F-1.  With removeable AE Prism for aperture priority and titanium focal plane shutter.  Extremely heavy and solid built SLR.  During the same period, Minolta produce a full range of MC Rokkor lenses to fit this "X" body (or SRT body), MC indicating meter coupled - An MC lens mechanically couples to the camera body and communicates the f-stop to the metering system in the body.  Please take note that these manual lenses are not inchangeable with the autofocus systems.
Minolta XK/XM/X-1 Professional SLR
Pictures above shows the "XK" and "XM" variant.  Other than the name different, the cameras were essentially the same. 
During the years of production, there were some improvement/modification done to the camera.  The most common observation was the back cover DIN/ASA scale with film cover holder incorporated (see above right picture).

During the early production from the 2 million serial number (2 XXX XXX), the battery check button and window has a seperate press bottom on top (and without the red len) which different from the newer 3 million serial number (3 XXX XXX), where the newer has the same of those  XE-1/7 (bottom right).  Also, the Prism release button was changed from fully chrome to black and chrome.  The wording "MINOLTA CAMERA CO., LTD" under the winder were removed, and the bottom plate white wording "MADE IN JAPAN" were replaced with an engraved "JAPAN" in black.  However, the most significant modification for the last of the model was the removal of the mirror "vibration absorbing curtain" - the moving plate just behind the mount!  Perhaps some improvement has done to the mirror mechanism that render the "curtain" redundant!