Antiquarian books are rare and old books of interest to collectors. A person who collects antiquarian books is typically less interested in reading the book than in owning and preserving it.
Antiquarian book collectors focus on books that are particularly old or otherwise unusual. First printings are prized as are books that were dedicated or signed by the author. The book's uniqueness, physical condition, print style and availability are all taken into consideration. A first printing of "Alice in Wonderland" is probably worth less to a collector than a later printing dedicated and signed by Lewis Carroll.
In the United States, much of the trade in antiquarian books is centered in Philadelphia and New York City, as of 2014; however, the Internet brought services such as Abe Books and Biblio to every computer, making it easy for antiquarian collectors and booksellers to find one another.