There's a version of Billy that is deeper (39cm = 15.35in), but maybe only in some regions: https://www.ikea.com/gb/en/p/billy-bookcase-white-90401932/ https://

There's a version of Billy that is deeper (39cm = 15.35in), but maybe only in some regions: https://www.ikea.com/gb/en/p/billy-bookcase-white-90401932/ https://www.ikea.com/gb/en/p/billy-bookcase-white-90401932/