Examine the entire book for clues. If you have access to the rare book, a thorough inspection may uncover useful information. Most books have information regarding the publisher and more on the first few pages. Look over the dust jacket and binding for additional information. Use any clues you may find to follow up on the publishing date. For example, locating the symbol for a publishing company can be a huge step in finding out when the rare book was published. The book may be rare because the company that published it went out of business.
Research the author. Even well-known authors can be responsible for producing rare books. For example, "The Mutiny of the Elsinore" by Jack London is considered a rare book due to the limited number of copies published. The term "rare" is also used to describe first-edition prints as well as autographed copies. Use a site such as Book Reporter to get details of when books were written and published.
Use the ISBN of the rare book. An ISBN can unmistakably identify important details about each book, including the publisher. Look on the back cover of the book for the ISBN bar code. Input this information into a site such as Alibris, which can use this number to track the book's publishing details. If you don't have access to the book, input the title into the site and it can also give you an ISBN.
Enlist the services of an established rare book collector or dealer. These professionals take rare book knowledge seriously and may be able to provide the answers you seek. Gather all known information about the rare book before making contact. If you seek information about a specific printed edition, making this known upfront can save time. Try a site such as Abe Books, which can access information from thousands of rare book dealers.
Take your search to a rare book database. There are a variety of websites devoted to the cataloging of rare and out-of-print books. Use a site such as Book Finder to search for the book publisher. Type in the name of the book and author and wait for the results. Click on the best match and read the book's details, including the publishing company and publication year. There may be different years available depending on whether the book is a soft cover or a hardcover.