On Demand Books' new machine, Espresso, may just change the way book stores stock books.  That may make it easier for you to find that out-of-print treatise.  Espresso will also ensure that your novel of choice is in stock.  The machine - which prints about 100 pages per minute - currently stores about 500,000 title, but the company plans to expand its offerings to over a million.  And at approximately $15 per book, it's relative affordability may make book-buying - and dare I say reading - a favorite leisure activity once more.