A bookshelf divider has to work from both sides

A bookcase used as a room break is seen in the round. The cheap hardboard back you never noticed against a wall becomes the view from the dining table.

Choose an open-back or a finished-back piece. Keep the densest objects in the middle shelves so the divider has a spine. Leave the lowest shelf boring — bags and shoes will find it anyway.

In the studio, check sightlines: you should still see a window from the sofa, or the divider is a wall and should be priced and placed like one.

If the case is unstable once it is not against plaster, it is not a divider. It is a hazard with books on it.