Everything is miscellaneous : the power of the new digital disorder, by David Weinberger. New York : Henry Holt, 2007.
Reading books on information management theory for fun isn't something I'd usually admit to, but this is a marvellous, un-put-downable read. Weinberger starts with an interview with the manager of a Staples store to discuss organisational principles in retail; and moves on to discuss the randomness of alphabetisation, Aristotelian definitions, "lumping" and "splitting", Linnean classification, the periodic table, the Dewey Decimal system and Ranganathan and faceted searching, all in completely comprehensible terms using (frequently amusing) real-world examples; before moving on to tackle the (dis)organisation of the second-generation Web.
Weinberger has a positive outlook on the "third order" of information, seeing great creativity in the apparent chaos of the web; but is not entirely in the camp of people who believe that more advanced machines will create an organised utopia.
If you have any interest at all in how knowledge is organised (whether as an information or computing professional, or at the level of wondering why Amazon is suggesting these books to you, and what ads Google decides to position next to your search results), this book is fascinating and immensely readable.