This is not a joke. There is, in fact, a book in the Library of Congress with this subject heading. Beth Dunning, in "Newsflash! Subject Headings not boring!" (Marginal Librarian 12:2), suggests that "someone at the Library of Congress has a sense of humour, and is taking advantage of the fact that no one is watching." But in this particular case, the subject heading may be argued to have been correctly assigned because the book is a collection of papers read at a conference on drilling and rock mechanics.
Check out the article for more hilarious subject headings. And if you have any of your own (preferably available through an online catalog), please share them by clicking on "Add a comment" below.
Boring--Addresses, essays, lectures
