You can't expect every book to make worthy subjects fascinating (e.g. Freakonomics), but this collection of lengthy (so, so lengthy) descriptions of mostly medical classifications is as dull as they come.
Even for academia, the emphasis of description, the paucity of analysis and the complete absence of any practical guidance is disappointing.
OK it was written in 1999, but there is nothing about the emerging challenges of information classification on the Internet at a time when Yahoo! etc. were offering browsable taxonomies of web sites.