We use this bookcase horizontally, and while we love the way it looks and have gotten compliments on it, it is not the most stable. I would not put heavy items on the top most shelf; the whole bookcase can sway side to side so also don't put anything on it you wouldn't want to risk tipping over.. I've had this for less than a year and picking up and moving the bookcase from one room to another caused some of the joints to come unattached.