Missile Cruiser - Terran Romulan War Era
The Missile cruisers were medium to heeavy ships carrying as many missiles as could be jammed in the hull.
They were intended to be the main stand off strike arm of the Fleet, and were escorted by Frigates and Destroyers. In their military role, they were moderately successful.
After the war and the founding of the Federation, Terran Missile cruisers were used briefly for patrol and security purposes by Starfleet, but were quickly retired to planetary defense roles for Earth Force.