This bookcase consists of three units, shelves and trim that I made in my shop and assembled on site. The kickboard, casings and crown mold are installed after the units are mounted. Each shelf has a rounded 1 1/4″ facing that hides the chrome pegs that support them. Peg holes are spaced at 2″ intervals. I generally use finger-jointed primed Centurion pine for shelves and the frame, rather than whole boards, which tend to warp.
On this job, the floor had a significant dip under the bookcase. To assure that the shelves would be lined up, I installed three of the shelves on their pegs to see how they lined up, and the shelves followed the dip in the floor. After shimming under the middle of the unit I screwed the three units together and assembled the bookcase to the wall. The kickboard hides the shims.