"Bibliographies can help you answer those questions. That said, you should know that not all bibliographies are created equal. In some cases, one reference will do, but in most cases you'll have to consult more than one source. Sometimes, a reference is no more than a bare-bones list and its best utility is being able to say about the book in question it's "not in" a standard authority.

"For example," he continued, "in a field like Science Fiction the work of EF Bleiler comes to mind. It's expected that a specialist will have such references. Few of us have the widely recognized expertise to say 'First Edition, complete as issued', as well as provide a commentary on why the book is important. Citing standard references when you make such a statement lends credence to your claim that the book is 'a first, complete as issued and important because....'

"In other words, the first time you try to sell a book on the California Gold Rush to an important California library like the Bancroft, they probably won't recognize your name Joe Blow - Bookseller, but they will certainly know Gary Kurutz's California Gold Rush a Descriptive Bibliography of books and pamphlets covering the years 1848-1853.

"Many sellers I see on the web cite references without knowing what they are, just copying another bookseller's description. In my opinion that's not a good idea. If that bookseller is in error, you're going to be in error, and ultimately it's your reputation that will suffer.

"What if the customer asks you about the reference, and asks for a Xerox copy of the citation to accompany the book just purchased? You'll look less than professional if you can't answer the question and supply the proof."

Check it yourself
"My personal philosophy is not to cite a reference I haven't personally checked, either through consulting the reference in my own library, or getting a fax from a colleague, or heading over to the appropriate library and checking it there. In this business your reputation is paramount, and certainly not worth sacrificing by taking shortcuts.

"Finally," he said, "be sure you know what parameters are encompassed by the bibliography you're citing. For example, the Pforzheimer Catalogue of Early Books in English covers the years from 1475 to 1700. On-line, I saw a listing for a 1702 English book saying, 'Not in Pforzheimer.' Well duh!"

Arriving at commercial value
So how do you arrive at a value for a given book? The method Zoschak uses is a series of questions and answers:

"First, what do I have? After determining edition and condition, I note whether or not it has any special attributes, such as ownership signatures (author or otherwise) or publication specialty, for example, Advance Review Copy.

"Next comes availability: Are copies currently available and in what quantities? If yes, how does this copy compare to those currently on the market? Who's at the high end... what are the copies like at the low end?

"If no copies are currently on the market, then a determination of the book's sales track record is in order. I try to look at old bookseller catalogues, price guides, and auction records. With that information it's not hard to arrive at an estimated current market value.