NEW YORK – How do you know what the books on your shelf are worth? Should you stash that box of eclectic first editions your grandmother gave you? To rebind or not to rebind? Here, the top ten factors to consider when valuing books according to Richard Austin and Selby Kiffer, specialists in Sotheby’s Books & Manuscripts Department.

1. Primacy
As in life, it pays to be first. Books containing the earliest known mention of a significant character, idea or theory in print carry great meaning to collectors. Similarly, historical primacy can be highly valuable – some books are desirable because they were the first appearance of a certain language or the first book printed in a particular location, whether it’s Pennsylvania or Antarctica.

2. First Books (Not First Editions)
Many people hear “first edition” and immediately assume a book is expensive – but remember that every book ever published had a first edition. (And many didn’t enjoy a second.) What makes a valuable first edition is the perfect confluence of rarity and demand – which is why, while there are exceptions, an author’s first book, typically printed for a small audience, is the one most likely to achieve impressive prices. By the time a popular writer releases their second, third or fourth novels, they have higher demand and larger edition sizes to match. While a hardcover first edition first printing of J.K. Rowling’s debut book Harry Potter and the Philosopher’s Stone, of which there were only 500 printed, can go up to $45,000, a hardcover first edition first printing of the second in the series, Harry Potter and the Chamber of Secrets, costs around $7,000.

3. Condition
As with most collecting categories, a book’s condition helps determine its value. However, because bindings didn’t become uniform until the late 19th century, distinguishing condition is much more relevant in recent editions. The most important factor to look for in modern books: dust jackets. In a perfect dust jacket, a first edition of The Great Gatsby could be worth $400,000. Without the jacket, you can expect F. Scott Fitzgerald’s classic to drop to $8,000.

4. Contemporary Binding
Collectors generally search for books in their original (or contemporary) binding, rather than editions that have been re-bound. Even an older 18th century book, such as Gulliver’s Travels, is going to be worth more in its original calf, despite the fact that the overall condition will almost inevitably appear less than pristine.

5. Completeness
If a book was issued with multiple parts, such as colour plates, maps, or illustrations, look for a copy that is one hundred percent complete in order to reach its full potential value. Removing the map from Lewis and Clark’s journals or framing 20 of the 500 plates from John James Audubon’s Birds of America will lower their respective prices dramatically.

6. Provenance
Did someone important own a book? Did it come from a celebrated library? Provenance, or history of ownership, can greatly enhance value – so much so that volumes worth intrinsically less than ten dollars can jump up to $60,000–80,000 if they belonged to a famous individual like George Washington. This becomes even more relevant if the former owner had an association with the book’s author or subject. (For example, in Washington’s collection a book on history would trump a novel.) Signatures and bookplates add value because they provide evidence of ownership.

7. Quality of Printing
Many collect books as objects, and hunt for particularly beautiful, finely printed masterpieces. In this case, a book doesn’t have to be the first edition from an author like Giovanni Boccaccio, but can be any one of his printings that exemplify quality of craftsmanship.

8. Quality of Binding
Similarly, others collect fine bindings, such as 20th century French Art Deco and 17th or 18th century English, which are considered works of art. Here again, the content doesn’t matter as much as the artistry at hand.

9. Illustration
Another physical characteristic that can add value to a book is illustration – either as an example of primacy, such as the first depiction of snakes, or as work by an artist (especially a famous one) like Henri Matisse’s limited edition of James Joyce’s Ulysses.

10. Rarity
Rarity is the principle most often ascribed to a book’s value that – in reality – plays the least important role. In fact, rarity only matters if the book has demand, which is driven by the nine criteria above. So while it may be harder to find a tenth edition than a first edition of Huckleberry Finn, that doesn’t mean that it’s worth more.