Classification Made Simple
A solid introduction to classification, cataloging, indexing, and organization structures. It’s a textbook, so some of it gets necessarily academic.
I enjoyed the emphasis on history. Raganathan is covered extensively, as is Bliss. There are long sections on category labeling, which is probably obsolete-ish now, but was valuable to get perspective on where we’ve come from.
Chapters are quite short.
This is the 2009 version, updated from the 2002 version. Still, the final chapter on Internet technology seems really dated to me (it would be five years old, as of this writing).