These books are an essential resource for my vocation as librarian. Under the Dewey Decimal System (DDC), informational books are grouped in order according to the number assigned to them. This consistent application means that, once you know the Dewey number for a subject you are interested in, you can easily find books on the shelves of any library that arranges materials by this system.

DDC 22 is the 22nd edition of the classification system, originally authored by Melvil Dewey.

The DDC is under continual revision by a committee of editors under the OCLC, a global library cooperative, and at the time I purchased my four-volume set, the OCLC had recently published its 23rd edition. Well, being on a budget, I couldn't justify a purchase of several hundred dollars, but a used set of DDC22 was thankfully within my reach. It lists Dewey Decimal classifications numerically and also provides an index to quickly look up specific subjects. ( )