Staff Writer (Updated: 11/7/2015):
The MT-LB was developed as a direct replacement for the aged AT-P artillery tractor line. The design was largely formed from the work that also begat the successful PT-76 Amphibious Light Tank which was produced in over 12,000 examples. The initial product was the MT-L which then evolved to become the armored MT-LB. Production was assisted by the type utilizing many off-the-shelf components in circulation, and readily available, to the Soviet Army at the time. Manufacture was headed through the famous Kharkov tractor facility. The designation of "MT-LB" is born from the Russian translation describing "Multi-Purpose, Light-Armored Towing Vehicle".
One of the key qualities required of most any Soviet armored vehicle was amphibious support allowing the vehicle to cross moving water sources under its own power. The alternative was traversing bridges and similar checkpoints or arranging for engineers to construct a make-shift bridge over the span of hours and maybe days. The MT-LB was designed with this quality in mind, fully-amphibious, and propelled in the water by its own tracks, negating the need to activate a dedicated propulsion system.
Another key quality consistent with Soviet-inspired armored combat vehicles of the period were low silhouettes to make for a harder target to spot, identify and engage along the horizon. The MT-LB, therefore, was granted as low a profile as possible. It lacked any large, powered turret (a small, one-man installation was used instead) with the hull consisting of a near-flat glacis plate, armored visors at the front panel and a flat roof line with rounded hatches for the crew (a pair of hatches are set along the forward portion of the hull roof line). Armor consisted of welded steel for maximum protection (14mm at its thickness). A typical operating crew was just two men with up to 10 or 11 passengers in relative comfort (inward-facing folding canvas seats are provided).