This is one of the reasons why I love watching this show. The way the writers make everything come full circle. You can watch an episode and the gang are all doing their own thing and yet somehow it all comes together.
I love how the evil gym teacher had ended up having the book all these years! I loved seeing George with an Afro, and Jerry with long stringy hair, priceless!
But without a doubt the crowning gem of this episode has to be the performance of the actor who played Mr. Bookman, Philip Baker Hall! His speech about the evils of those who don't return books, and how they don't care is absolutely brilliant.
I think he should have gotten an Emmy for this episode. He makes this one of the classic episodes!