You can build a small three-shelf bookcase from pine in about two hours using pre-measured lengths of boards and wood screws to hold the shelves securely.
Finish the plywood boards and shelves with a stain finish and let them dry overnight. It's easier to do this before assembling the bookcase because of all the tight corners when it's put together.
Lay both sideboards beside each other. Measure and mark the places on the sides of each board where the shelves will be attached. This is ¾ inch on the inside and outside where the shelves will be attached both front and back. The top shelf will form the top of the bookcase, and the bottom shelf will be the base. Mark the same places where the shelves will fasten on each of the shelf boards.
Drill the shelf holes on the outside of the sideboards and on the edges of the shelves.
Place one drop of wood glue into the holes on the shelves and fasten the shelves and sideboards together with countersunk wood screws. Repeat this process on the other sideboard until you've formed an open bookcase.
Fit the luan board to the back of the bookcase and nail it securely in place.
Use a lacquer finish to protect the bookcase. Let it dry thoroughly after each coat. Use at least three coats of lacquer for best protection.
You can add decorative moulding to the front and sides of the bookcase.