Granted, it's my fault for not getting out and measuring stuff.  But this photo ON THE ADVERTISEMENT is totally false advertisement.
This photo shows that this bookcase will hold 1" binders.

I only bought this bookcase to hold my binders for grad school.  And not a single one of them will fit.  They are all too tall and too deep.

It's put together now, so I'll find another use for it.  But now I have to find another bookcase for my grad school stuff.