A two component shelving system comprising: an outer structure comprising: two laterally opposing first and second sidewalls (18,19); one or more elongated horizontal front panels having laterally opposing ends, each end connected to a sidewall (18, 19) along a first fold line a rear wall integrally connected to one of the sidewalls along a second fold line and adhesively connected to the other sidewall, the rear wall defining one or more rear wall slots and one or more shelf front flaps, each shelf front flap hingedly connected to a front panel along a third fold line each shelf front flap comprising a tab; and an inner structure comprising: two vertically elongated connecting flaps adhered to the first and second sidewalls (18, 19); one or more elongated inner horizontal support panels having opposing ends connected to the vertically elongated connecting flaps along sixth fold lines; and one or more shelf rear flaps, each shelf rear flap hingedly connected to an elongated inner horizontal support panel along a fourth fold line each shelf rear flap comprising a tab configured to mate with a corresponding rear wall slot each shelf rear flap defining a rear flap slot configured to receive the tab of a corresponding shelf front flap, characterized in that the outer structure further comprises a rear wall glue flap affixed to the rear wall along a fifth fold line. two laterally opposing first and second sidewalls (18,19); one or more elongated horizontal front panels having laterally opposing ends, each end connected to a sidewall (18, 19) along a first fold line a rear wall integrally connected to one of the sidewalls along a second fold line and adhesively connected to the other sidewall, the rear wall defining one or more rear wall slots and one or more shelf front flaps, each shelf front flap hingedly connected to a front panel along a third fold line each shelf front flap comprising a tab; and an inner structure comprising: two vertically elongated connecting flaps adhered to the first and second sidewalls (18, 19); one or more elongated inner horizontal support panels having opposing ends connected to the vertically elongated connecting flaps along sixth fold lines; and one or more shelf rear flaps, each shelf rear flap hingedly connected to an elongated inner horizontal support panel along a fourth fold line each shelf rear flap comprising a tab configured to mate with a corresponding rear wall slot each shelf rear flap defining a rear flap slot configured to receive the tab of a corresponding shelf front flap, two vertically elongated connecting flaps adhered to the first and second sidewalls (18, 19); one or more elongated inner horizontal support panels having opposing ends connected to the vertically elongated connecting flaps along sixth fold lines; and one or more shelf rear flaps, each shelf rear flap hingedly connected to an elongated inner horizontal support panel along a fourth fold line each shelf rear flap comprising a tab configured to mate with a corresponding rear wall slot each shelf rear flap defining a rear flap slot configured to receive the tab of a corresponding shelf front flap, characterized in that the outer structure further comprises a rear wall glue flap affixed to the rear wall along a fifth fold line.