Regretful printer, by John DePol, from The Legacy Press.

You don’t want to be doing one of these. It means you (or one of your colleagues) have screwed up, and badly enough to warrant the expenditure of quite a bit of money.

Errata, also referred to as Corrigenda, are mistakes and misprints discovered after  a book has been printed. They may be joined by their cousin Addenda. In the early days of printing, when it took quite a while to work through the setting and printing of a book, Corrigenda and Addenda might be incorporated into the first printing, in the front matter which would be printed last. Some early printers corrected errors and omissions straightforwardly by hand-written additions.

The whole subject gives bibliophiles conniptions: they agonize over things like whether a book which had an erratum slip is complete if the erratum slip has gone missing — which of course tends to happen a lot.

If the mistake is embarrassingly silly it may be taken care of by a cancel — a completely new page tipped in in place of the ghastly original. An erratum slip may tend to advertise the carelessness of the author’s proofreading, and occasionally may be there as a silent admonishment by a frazzled publisher. Just dropping an erratum slip into the book is the cheapest way of dealing with the problem — other of course than simply ignoring it and assuming nobody’ll notice, which is more and more our modern attitude. But really an erratum slip should be tipped in somewhere near the end of the front matter: if you’re going to go to the expense of doing one, you really want the reader to get the benefit of the information it carries.

See also Anti-decluttering for a couple of examples.