Let it be known that I abhor end notes. Can't stand them. I'm a compulsive reader--I feel compelled to read every word in a book. If I'm going to read any of it, I want to go all the way. So I feel uneasy bypassing a note in a book or article. Scholarship is full of them (the scholar Bruce Lincoln once defined myth as scholarship without footnotes, a thought worth exploring), and the trend is to put notes at the end of a book, requiring readers to flip back and forth between the page they're reading and the notes at the end. This drives me nuts, especially when the notes aren't worth while.
Footnotes, on the other hand, can be invigorating. There are a number of books with good footnotes. Stephen King's Danse Macabre comes to mind.
The humorist Christopher Moore puts footnotes to good ends in his book Fool. He uses this device well throughout the book, to gloss archaic
terms and insult the French, but on page 6 he gives us the greatest footnote in
the history of footnotery. It exists because of this sentence: "Bubble
dropped a gutless trout into a bushel of slippery cofishes." And if we're
interested in what he means by that final word, all we have to do is glance
down to the bottom of the page, to find, "Cofishes--other fish in a group,
coworkers, cohorts, etc. Shut up, it's a word."
If, upon reading the first five pages of Fool, you doubted you were
beholding a work of greatness, that footnote would exorcise your doubt.
A book full of notable footnotes is Book: A Novel, by Robert Grudin. I don't know where my college roommate Mike Judd got a copy of this, but he thought it was funny so I read it, too. The story is sort of a mystery set in the world of university politics. At one point, the footnotes actually stage a coup and take over the book proper. It's pretty meta, and I appreciate the figurative notion of scholarly apparatus blotting out the ostensible point of the story even more now that I have experienced graduate school.
Dustin Long used footnotes in his novel Icelander. Here is one of the finest: 37. Hubert Jorgen in conversation: "Forgery, I think, is perhaps the pinnacle of self-expression, paradoxical as it sounds. There's a school of thought that says the more constraints put upon a piece of art--rhyme and meter, say, in the case of poetry, or photo-realism in the case of painting--the more impressive that artwork is if executed successfully. Well, what could be more constraining than forgery? And if you manage yet to express yourself within that rigorous framework, what, then, could be more impressive?"
These are but a few examples of footnotes that are worthwhile, even necessary parts of the books they supplement.
There are, I must say, some cases of acceptable and even magisterial endnotes. The first one that comes to mind is Henry Glassie's The Stars of Ballymenone. After checking a few as I read through the book, I decided to just wait and read them all at once after I finished. It was worth it. Sometimes I flipped back and read the relevant passages in the main text, too.