Measure the length and width of the bookshelf. Purchase a shade that fits inside the bookshelf and is long enough to reach the floor.
Measure down about ¼ to ½ inch from the top of the bookshelf and install brackets on the inside walls. This will ensure the top of the shelf will not impede the movement of the shade. Follow the manufacturer's instructions on bracket installation. Mark where the brackets go on each side and make sure they are level. Screw them in securely on each side of the top of the bookshelf.
Slide the roller shade into the brackets and pull the shade down to hide the contents of the bookshelf.
Measure the length and width of the bookshelf and purchase an appropriate tension rod and two curtain panels that will reach to the bottom of the bookshelf
Insert the rod through the casing of the two curtain panels. Curtain panels should be wide enough to close when they are installed. To make a gathered effect, purchase panels that are wider than the bookshelf. Purchase two 24-inch-wide panels for a bookshelf that is 2 feet wide
Extend or tighten the tension rod by twisting it. Make sure the curtains are facing the right way before installing the rod. Place the tension rod at the top of the bookshelf with the rubber ends on the inside wall. Secure it so it will not fall, and arrange the curtain panels so they close and gather evenly.