When you can't find a convenient nook for a set of narrow storage shelves , you can often create one by recessing the shelves into the wall itself. Choose the location for your shallow shelving unit before you build the project to make sure it will fit. Start by looking for a space with no obvious obstructions. Locate the studs with a stud finder. Some stud finders can also locate electrical wires and plumbing pipes inside walls. When you've found a promising spot, cut a 6-in.-square inspection hole between the studs. Use a flashlight and a small mirror to inspect the stud cavity for obstructions. You often can modify the size of the cabinet to avoid obstructions. When you find a good space, mark the perimeter of the opening and use a drywall keyhole saw to cut it out. Measure the opening and subtract 1/4 in. from the height and width to determine the outer dimensions of your behind the door shelves. For standard 2x4 stud walls with 1/2-in.-thick drywall, build the cabinet frame from 1x4s that measure 3-1/2 in. wide (see illustration). If your walls are different, adjust the depth of the frame accordingly. Then add a 1/4-in. back.We screwed 1/4-in. pegboard to the back so we could hang stuff from pegboard hooks. Add casing that matches the trim in your house. Drill holes into the sides to accept shelf supports. Shelf supports fit in 3mm, 5mm or 1/4-in. holes depending on the style. Install the cabinet by slipping it into the opening, leveling it and nailing through the trim into the studs on each side. Use 6d finish nails placed every 12-in. along both sides. Don't want to open your walls? Check out these other easy shelving ideas