Types of Signed Books
There are many variations of the signed book going back to the advent of publishing. Books have been signed on just about any of the first few pages of the book, starting with the first free endpaper. It is really a matter of choice, and collecting preferences. The important thing is that it is signed by the author. Some collectors prefer that a book is signed on the title page, but will choose one of the following variations over an unsigned copy.
Beginning several years ago major publishers and book sellers started using tip-ins for author signings. A tip-in is a page signed by the author that is inserted into the book either during or after binding. The use of the tip-in has greatly expanded the number of signed titles that are available to collectors, as page signing is a much more effective way of producing signed books. Large increases in shipping costs, and damage during transit, have made sending books to authors for signing largely a thing of the past.
Some publishers have moved to sending the author endpaper blanks for signing. These sheets are then used when the book is bound, leaving the author signature appearing on the first free endpaper.
Tip-ins are now almost the only method that publishers use for author signings, exclusive of live events at local bookstores or other venues. Almost all signed books sold by major retailers are of the tip-in variety.