The majority of the books I offer for sale on ebay would fall under the category of Second-Hand books and not Rare.
Is my book Rare and/or Very Important? – Only a very small percentage of books would actually be considered rare by books specialists. Certainly supply & demand is always a factor, but that can also be subjective. Some of the more very collectible books are major editions in arts & sciences (early editions of prints, inventions, etc.). At times these books were suppressed/destroyed in their country of origin, making any remaining copies much more valuable. Special bindings and the initial use of a new printing process can also increase the value dramatically. As always, condition is an important part in establishing the value of a rare book.
Where do I find rare books?
As books are easy to transport they can turn up everywhere, from private libraries to attics, basements, and barns. Books found in place other than properly controlled environments (libraries) often show signs of neglect (rips, water damage, etc.) and these have considerable less market value to a collector.
Are all old books rare? In a word – no.
What is the difference between a rare book and a second-hand book?
Very old books certainly have value, but the condition and availability is critical. There will always be a market for them, but the price is always reflective of the availability and condition of the piece.
Books found in attics, basements and yard sales often appear to be old, interesting, or valuable; and while it is possible to find a rare book in any setting, the second-hand book (a used book not distinguished by its edition, binding, uniqueness or overall condition) is more likely to be encountered. There is a market for these second-hand books but the actual value will be considerably less than for a rare book. Even if a book is quite scarce or has had a small printing run), it does not always mean it will have significant value unless there is demand for it among collectors
Condition is a major factor in determining a book's value. Condition refers to both the book's external physical appearance and to the completeness of its contents.
A book that has been rebound or repaired must be very important or in high demand to be of substantial value. Loose pages are a defect and missing pages or illustrations are a major fault that will make most books almost valueless.
Bibles - for the most part, Bibles are not considered rare, other than some of the earliest printed Bibles dating from renaissance times and a variety of sixteenth- and seventeenth-century oddities. Bible generally have more sentimental value to families than value in the open market
Sermons and Religious Instruction – other than those written by major figures in the specific religion, most have little value.
Collected Editions of an Author's Works – generally not a high value, unless superbly bound in high quality leather and well preserved.
Encyclopedias - In general, encyclopedias are bought for their current information and unless there is a complete set of a First Edition (1700s), they have little monetary value.
Textbooks - Old schoolbooks rarely have high monetary value and are of more interest to a collector who used it as a child.
Reprints and Facsimiles – little or no value
Newspapers, Magazines, and Comic Books – while popular among many general collectors, these have little value to Rare Book collectors
Old letters, scrapbooks, and documents – unless written or signed there is an important historical figure, they are generally not very valuable and the condition is always very important.
What is a first edition?
In the strictest sense, "first edition" refers to a copy of a book printed from the first setting of type, constituting the first public appearance of the text in that form. The liberal use of the term "first edition" has made it seem synonymous with "scarce" and "valuable." This is by no means the case. Most books appear in only one edition.
Signed or marked up by a previous owner or autographed by the author more valuable?
The association of a book with a previous owner can add to its value, depending on how well known the previous owner is and how important the book was in relation to this person. Indication of previous ownership may be in the form of a bookplate, signature, inscription, or other distinctive mark.
Finding a twentieth-century book signed by its author is quite common. Authors routinely make publicity tours across the country signing copies of their books, and their signatures alone do not have much importance. Still, autographed copies carry more value for collectors than unsigned copies. When trying to determine the worth of an author's autograph, remember that books are signed for different reasons. In ascending level of interest these are: books signed as part of a publicity event, copies inscribed by request of the owner, copies of a book inscribed and presented by the author. The autographs of certain authors are always more desirable than others, and fads and fancies change so that only someone familiar with the market will be able to give a precise idea of the value of a signed or inscribed copy.
How can I keep my books in good condition?
Books are very sensitive to temperature and humidity. A cool dry environment is best. This usually rules out storing books in the basement or the attic. Sunlight, especially direct sunlight, is detrimental to books. Sometimes people go to the opposite extreme and store their books in cardboard boxes, first wrapping them in newspaper or plastic. Both materials can cause damage. Newspapers are printed on highly acidic paper, and this acid will enter the book and stain it. Plastic tends to be airtight, allowing mold to develop with the slightest moisture, and some plastics, like newsprint, are acidic. Books kept in bookcases under conditions comfortable to humans will survive for years, but even a solid book placed in hot or damp conditions will soon deteriorate. Very large books such as atlases, bound newspapers, or art folios need extra care. If at all possible they should lie horizontally on the shelves rather than stand vertically. Under no circumstances should any self-adhesive tape be used to repair torn pages. As the tape ages it will make a sticky mess that will seal and stain the pages and become almost impossible to remove.
Where can I give/donate my old books – Many organizations receive books as donations and hold book sales to sell them at moderate prices. Volunteer thrift shops, charitable organizations, and church and school bazaars often are eager to receive book donations.
How do I describe my books for resale? - Any listing of books should include the name of the author, the exact title, the name of the publisher, and the place and date of publication. This information should come from the title page, not from the binding or dust-jacket. The description also should include some brief comment on the book's condition and the presence or absence of a dust jacket.