Ikea has almost too many choices! Their "Billy" shelves are 10 inches deep, and I would choose 12 if they had them -- but the next shelf depth I found is 13 3/4 for the unit, 12 5/8 for an extra shelf so I guess that is what I'll get. Both Brimnes and Fjalkinge bookshelves come with two drawers. Someone pointed out that drawers at the bottom will be more and more welcome as this retiree ages.