Westsider Rare & Used Books has an inventory of approximately 40,000 books in a tall and narrow space on New York's Upper West Side. So tall that library ladders are required to reach the books on the top shelves. Stairs lead up to a mezzanine level that occupies the rear of the bookshop.

Books cover a wide range of subjects including f iction, literature, biography, film, Judaica, modern first editions, art, illustrated books, graphic design, comics, graphic novels, children's books,  architecture, antiques & collectibles, American history, Black history, Eastern art, LBGT, environment, philosophy, psychology, prints, and ephemera.

The current owner, Dorian Thornley, began working in the bookstore in 1995 and became the sole owner in 2018. Founded in 1984 the bookstore has occupied various spots on the Upper West Side settling in its current location on Broadway between 80th and 81st Streets. In 2019, due to rising costs, Thornley announced the closing of Westsider Books causing neighbors and customers to rally and create a crowdfunding raising sufficient funds to keep the bookstore open.

Used bookshop with a 40,000 book inventory, double-height ceiling and tall library ladders to reach the upper shelves.