After a couple of days off I got back on track today and milled all the red oak stock to proper
thickness (3/4") and ripped enough 2-inch wide pieces to fabricate the bookcase face frames. Got
the smaller of the two cases fully installed by the end of the day and will do the other tomorrow.

This shot shows the difference between what the cases look like with and without the frames.
Again, the frames give a case all the lateral strength it needs. With the backs they will be completely rigid.