Excuse me, but my appendices seem to be missing....
Libraries and bookshops have always been great places for people watching.
What's that guy with the pink mohawk doing with a copy of Finnegan's Wake?
I sometimes wander about such places trying to spot the readers or book buyers who are likely to be academics. You've probably spotted a few of them yourself--they're the ones who keep opening books from the back rather than the front.
Academics often judge books by their scholarly apparatus--i.e., all those things which help a reader verify the accuracy and currency of an author's work: endnotes or footnotes; a bibliography; an index; an appendix for matters that may require more detailed discussion (but would otherwise interrupt the narrative of the main text). This apparatus traditionally has been included at the back of English-language books.
It's harder to spot academic readers than it used to be, because a lot of publishers have ceased publishing the scholarly apparatus as an integral part of the book. Nowadays, the indices, appendices, bibliographies, etc., are just as likely to be included on a CD-ROM in a pocket inside the book, or made available via a website.
This poses some interesting questions. If scholars add such books to their private libraries, what happens when they no longer are able to access the CD-ROMs due to changes in technology? What if the websites containing such apparatus blink out of existence?
Using the indices might become a bit problematical. Ditto the bibliographies. Ditto the appendices.
It would be a pretty piece of irony if future scholars find books published decades ago, in which the scholarly apparatus was an integral part of the book, more useful than today's hybrids....