Here in Australia one of the charities runs huge book fairs every few months where vast amounts of literature are loosely organized in to subject sections. It's all volunteer labor and I believe the proceeds go to homeless people and victims of domestic violence. I have acquired some awesome old maps this way as well as rare and interesting works. Unless aggressively digitized, most of the data will become unobtainium at some point. One learns to respect previous standards of writing, editing, illustration, design, publishing and printing. Oh how the mighty have fallen!