So here is a book shelf project I did a couple of years ago. I actually did them in a couple of stages. These were constructed out of pre-fabbed pine shorts glued together I purchased at Home Depot, ply-wood, 1 x 2′s, 1 x 3′s and a simple chair rail for the crown.
The sides and shelves were constructed out of the pre-fabbed pine shorts and I boxed in the back with ply-wood. This was actually all I did for about a year and didn’t like the way they looked big and thin. So 6 months ago I added the 1 x 2 and 1 x 3 face trim and chair rail crown to give them a bulkier look.
I wish I would have done this all at once but they were done first to finish the room before Christmas and I ran out of time. Adding the detail last year really finished them off but doing it all at once I would have been able to give them that “polished” professional look.
Still, the wife is happy, and way cheaper then buying bookshelves and we got the look we wanted!