I made the book shelf 61.5 inches tall, making it tall enough for all to reach. I fit made the back starting from a rectangle them an arc to make that rounded top. I extruded that then started working on the walls. For that i converted entities and offsetted it by about .3 inches. I extruded that by 13 inches. For the shelves i made another sketch on the back with four shelves with equal distance in-between. I finished off by adding a support bar in the bottom corne and changed it all to oak.