Abstract: A truck trailer that can be loaded from the sides or from overhead and which allows cargo to be transported within an enclosure includes a trailer bed, and an enclosure that is linearly movable with respect to the trailer bed from a position in which the enclosure extends over the entire length of the trailer bed to a position in which substantially the entire trailer is uncovered. In certain embodiments, a roller and track mechanism is used for facilitating linear movement of the enclosure as a unit from an enclosing position to an open position.