Searching for different versions or issues of a book has become a fairly simple task with the creation of the internet. There are several sites that offer information on availability and pricing. When you are doing a book search, it's very important to know some details about the book or title before you begin researching. If you're searching for a book printed before the mid-1960s, it will be a little more difficult if you should need a particular version or require a copy with a dust jacket in good condition.
Write down the title of the book you are researching, along with the author's name, the name of the publisher, and any other information you may have. If you have the ISBN number for the book it will be much easier to find.
Books printed before the mid 1960s do not have ISBN numbers and therefore can be much harder to identify.
Go to bookfinder.com, input the author's name and the title of the book. This will bring up a listing of all books matching that author's name and title. Also check in amazon.com for matching listings. From these listings you can determine which edition is the one you are seeking.
Check each listing for the publisher and copyright date, if you are looking for a certain copy, such as a hard back or paperback copy. Hard backs may have different cover art or different publishers, and more recent copyright dates. Each publisher will have created a different binding. Mass market paperbacks may also have different editions with completely different bindings and publishers.
If you are seeking a book for a collector, it's a good idea to check the listings to see whether there is an edition with a dust jacket, as these are more desirable. It's entirely up to you which edition of the book you want and what condition you are willing to accept.
You can also check publisher's listings for the titles they have published. Check the listings for overprints or overruns; often, these editions are sold at discount prices.
In the event that you are searching for an out-of-print title, then the hundreds of used book stores on the internet will be a great help. They carry millions of titles.
If you are still unable to find the book you are looking for, submit your request to a book search service or participate in blogs and forums that pertain to books and authors.
The following resources will be a tremendous help in your research:

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