Public librarians use Dr. Dewey’s classification many times during the day. It is one thing to know we have the book, but quite another to be able to find it. The Dewey Decimal System makes this much easier. His system is the one that most customers are familiar with, and it is used in over 200,000 libraries worldwide. Dewey published his system in 1876. It continues to remain up to date with the 23rd revision published in 2011. Dr. Dewey did the revisions himself while he was alive.