The shelf line descends in steps like a staircase, which lets the unit sit beside an actual stairway or under a sloping ceiling where a rectangular bookcase would not fit. Six cubes come in two sizes - 29 x 11 x 15 in and 14.5 x 11 x 15 in - and the whole frame carries 400 lbs, the highest total in this batch. It spans 60 in wide and 64 in at the tallest point on an 11-in depth, weighing 68.5 lbs in white engineered wood. A user manual is included; assembly is required.