Cambridge Encyclopedia

For the person who was looking: http://www.abebooks.com
(Sorry I keep mentioning the website, but I'm poor and I save money on
much-desired books by getting 'em used in decent condition.)

I'm seeing the Cambridge Encyclopedia of Language going from anywhere
from $8 to $40, not including shipping.  Condition of the book varies,
but the bookseller descriptions in my experience are very accurate--often
even on the pessimistic side.  I'm personally not fussy about a crease or
two in a dust jacket, though others may be.  You also have your choice of
softcover or hardcover.

That's if you're hard-up for money.  Otherwise, you may feel safer
getting a new, unused copy.  :-)

Hope this helps!

YHL