The Online Computer Library Center is a nonprofit, membership, computer library service and research organization dedicated to the public purposes of furthering access to the world's information and reducing information costs. More than 50,540 libraries in 84 countries and territories around the world use OCLC services to locate, acquire, catalog, lend and preserve library materials. At least, that's what it says on their website, from which I cut-and-pasted the preceding sentence.
Recently, they did a survey to identify the 1000 books that are most often owned by their member libraries. Various editions of the National Census ranked first, The Bible ranked second, Mother Goose was third, Divine Comedy was fourth, Homer's Odyssey was fifth, etc. All of the books that ranked high on the list are either reports (like the Census) or books written by long-deceased authors. They're also all books that have been published in multiple printings for decades or longer by multiple publishers. There have, for example, been hundreds of different editions of Tom Sawyer from different publishers so it's not surprising that it came in at #17, which is still very high on the list.
And then you get to #18.
#18 is the highest-ranked book on the list that was created by someone who's still alive and who produced a book that comes from only one publisher in one edition. In fact, you have to go all the way down the list to #80, past many of the major works of Shakespeare, Dickens and Poe, to find another book of which that could be said…and then it's quite a drop down to the next book written by someone who's still alive. (You will also notice that all the books in the top ranks that are by living authors would be found on the same shelf in any bookstore.)
So what is #18 that places so high on this list, well ahead of books so esteemed that they made you read them in school? I think I'll let you look for yourself. Scroll down slowly until you come to it.
(And while you're over there, you might also check out their list of books that have been banned over the years. Notice how closely it parallels the list of books that libraries felt were important enough to stock.)