Once the curves have been cut and sanded, we'll cut the dadoes in the shelf standards. These dadoes do not cut all the way through the front of the shelf standards, as there is a more attractive option. Instead, we'll stop the dadoes about 1/2" shy of the front edge. To accommodate this stopped dado, we'll notch the sides of the shelves in a subsequent step.
The preferred way to cut these dadoes is with a stacked dado set in a radial arm saw, set to a 3/4" width and 3/8" depth. One dado will be cut centered on the center line of the side standards, the edge of which is 13-3/4" from the top and bottom of the side pieces.
The other two dadoes are cut three inches from the bottom and top of the side standards respectively.
If using a stacked dado set on a radial arm saw is not an option, you could also utilize a 3/4" straight-cutting bit in a router to cut the dadoes. Be certain to install a straight-edge to guide the router, and make shallow, progressive cuts until the desired 3/8" depth is reached to avoid burning the bit or the wood.
Finally, before we move on, we need to make some rabbets to accommodate the top-back and bottom-back pieces. These rabbets should extend down the inside-back edges of the standards, from the top shelf dado up to the top of the standard, and again from the bottom of the bottom shelf dado, down to the bottom of the standard. The best way to make these rabbets is with your router table, making certain not to extend the cut beyond the dadoes, as this mistake would be quite visible in the finished product.