Abstract: A truck box includes a planar base and curved side walls and is enclosed at the ends by a front panel at one end and by a tailgate assembly at the other. A pair of curved clamshell type covers are pivoted to the front panel and are spaced from the outer surface at the rear of the curved side walls, by rollers. Hydraulic jacks at the front open and close the clamshell covers and cable assemblies at each end of each cover guides the movement of the covers. When closed, the truck box is substantially cylindrical and, with the addition of two detachable segments at the rear, is completely sealed. When opened, easy access is provided to the interior. The tailgate assembly preferably includes two side portions which swing outwardly horizontally and a center section which swings outwardly vertically hinging from the top edge of the tailgate assembly.