The LK/LOK Program was the Soviet system for going to and landing on the Moon.
The LOK was an uprated "Soyuz" spacecraft, capable of carrying two crew to lunar orbit and spending up to eight days in space. It differed primarily from the standard "Soyuz" in that it had no "orbital module".
The LK lunar lander was a one-man vehicle, unlike the proposed but never flown two-man American LEM lander. Nor did it actually dock with the LK-Soyuz spacecraft. Rather, the cosmonaut space walked across to the LK and proceed down to the surface of the Moon.
The LK would land and then return with the cosmonaut and a small sample of Moon rocks. Rendezvous with the LOK-Soyuz and the cosmonaut would once again space walk, board the LOK, and the crew return to Earth. The LK module was left in lunar orbit and acted as an unmanned photographic satellite until its batteries were depleted.