Here is the bible for Oz collectors, Bibliographia Oziana published by the Wizard of Oz Club, copyright 1976 by Greene, Haff, Martin, Haff and Greene, this is the second printing of 1981 (right in main photo, the 1st printing has sold). They seem to be the same except the cover color and the list of Club books at the end, which had two additional books listed in the 1981 edition. Softcover, 103 pages. See contents page for what is included in this printing.
Trust me, if you want to collect Oz books, you need this book (and as you progress, also the more expensive and inclusive Book Collector’s Guide to L Frank Baum). Describes the different editions and states (printings) of all the major Oz books by Baum, Thompson and others. Also includes some odd rare editions. Impossible to navigate through the Oz series, which often don’t list other than the copyright dates, without a reference that gives you all the nitpicky details so you know what you’re buying! In very good condition with light fading only.