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 the first edition, from 1981. Softcover, 103 pages. A later edition 1988 edition includes a bit more information, but this is nice since it chronicles this early effort by Oz scholars.
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 this book which gives you all the nitpicky details so you know what you’re buying! Many photos also. In very good condition with a bumped corner and light age toning/wear.