I have found several treasures rummaging through old bookstores, but none greater than my most recent find.  

I spied out an old biography on H.L. Mencken for $1.00.  That alone was a find, but what was contained inside much better.  As I thumbed through to make sure it was a clean copy, I found to my utter astonishment that there were two personal letters from Mencken on his personal stationary.  And those two letters were just valued at $250 and $150 by a rare book dealer.  You can’t have that experience at your local Barnes and Noble!