Though closet space is usually abundant in a home, space for books collected over the years is typically sparse. Now you can get more space for your books, and use some of that closet space that is going to waste in one afternoon of work.
Gather your supplies. You will need lumber that is the length of the wall you want your books to be on. If the closet is wide enough, put shelves on either side instead of the back for more book room. I would suggest oak or another hard wood, because it will take stain better, and it will remain sturdy over the years.
You will also need to ask your lumber mill or home store which fasteners to use in the lumber you choose for this product. You will also need brackets sized for your lumber, and your fasteners. Screws are going to give you the sturdiest hold, but you are able to use crown staples if you are using pine for this project.
If you have access to a dremel, I would suggest routing out the sides of your lumber for your brackets. This will ensure a tighter fit in your wall, and a bookshelf with more longevity. A stud finder may also be useful, as you can screw your brackets into your 2x4 or 2x6 construction, allowing your bookshelf to really last the life of your home.
Find a color of stain that matches your wood trim, of if you are using a soft wood like pine, paint is sufficient. Make sure that you sand your lumber with 240 or higher grit sandpaper, and either use a paint or stain primer before you finish your shelves. This will give your finish something to adhere to, remove any imperfections in the wood, and allow you to have a more even coat.
If you are having a lumber mill cut your wood to size, make sure that you give them precise dimensions to 1/16 if possible. Remember, measure twice, cut once, will make sure that you have the right size of lumber.
Depending on the height of your closet, you will want to space your shelves between 2.5 -3 feet apart. If you know that you will have some taller books, allow for extra room towards the bottom of your shelving. If you are truly handy, you may want to use a wood burner and carve subjects into each portion of the shelves for that professional work. If you are like me, however, you may decide to rearrange your books from time to time, and this may not be practical.