An advance copy, also known as an advance reading copy or ARC, is a copy of a book released by its publisher before the book has gone to press for a complete printing. ARCs generally do not have the final dust jacket, formatting or binding of the finished product; the text of an ARC may also differ from that of the published book if the book is edited after the ARC is produced. ARCs are normally distributed to reviewers, bookstores, magazines, and (in some cases) libraries between three and six months before the book is officially released.

On rare occasions (for instance, the publication of an eagerly-awaited or controversial book), a publisher may require the recipients of advance copies to sign a confidentiality of content agreement. However, in most cases the sheer number of ARCs produced and their distribution makes that impractical. A typical genre publisher may create 5,000 ARCs for a new book by a moderately popular writer.

Publishers also produce uncorrected bound proofs, also known as galley proofs, in advance of publication. Galley proofs were historically only used in the editing and proof-reading process, but publishers have recently begun to use them as ARCs. These galley proofs may have bindings and illustrations similar to that of the final copy, unlike old-style galley proofs which were usually bound in plain paper covers and without illustrations. Galley proofs differ from ARCs in that ARCs are printed in full colour and in the same format as a published book, while galley proofs are generally printed in black and white and are significantly larger in size than most books. Publishers who produce their galley proofs in electronic form do not use them as ARCs.