Reading of text after typesetting but before printing. A proofreader compares the compositor's typeset pages to the original manuscript -- which is always a smart practice even when an author supplies the manuscript on disk, since anomalous coding errors often occur. (nb: One annoying thing about QuarkXpress is that it strips out formatting when you flow in text.) Editors and authors read for stray typographical errors, and sometimes make more substantive changes. Compositors generally charge a fee for "author's alterations" (AA) or any editorial changes. However, in this age of desktop publishing, many publishers are setting their own pages, making it cheap and easy to produce round after round of page proofs. If you can't do your own typesetting, see if you can make a deal with your typesetter that includes one round of corrections. Some typesetters are willing to give you the computer file with your page proofs so that you can enter the corrections yourself. It is wise to give your authors only one crack at page proofs and give them a strict, tight deadline (a week should be enough); authors can get cold feet at the end and make disastrous last minute changes. For the publisher who has typeset her own book, the first time changes will cost money is after the disk has been sent to the printer or service bureau to be made into film. When you make changes on the blueline proof (that aren't correction of printer's errors), you will be charged for a new piece of film on each page you make an author's alteration (or AA). Therefore, make sure to mark any printer's errors clearly with the letters "PE". In the digital age, broken type and weird blots are becoming a thing of the past, but check carefully for them anyway, as well as cropping problems and anything else that diverges from your vision of the book. See copyedit, redact, change order, typographical error, bombproof, sandwich, strike-through, proof, recension, pore, edit.