Books are arranged by call number, indicated by the blue arrow in the image below. Be sure to check the status of the book, too. If it says "available," the book is on the shelf. If the book is checked out, the status will say "checked out."
Books with call numbers A - N are on the first floor of the library.
Books with call number P - Z are on the second floor of the library.
Call numbers are in the Library of Congress system. Each letter corresponds to a certain subject. For a list of letters and their subjects, see http://www.loc.gov/catdir/cpso/lcco/.
Reference books, print periodicals, movies and music are on the lower level of the library.