In the book trade, a tipped-in page or, if it is an illustration, tipped-in plate, is a page that is printed separately from the main text of the book, but attached to the book.
A tipped-in page may be glued onto a regular page, or even bound along with the other pages. It is often printed on a different kind of paper, using a different printing process, and of a different format than a regular page. Some authors include loose pages inserted into a book as tipped-in, but in this case, it is usually called an insert instead.
Coffee table art books featuring high quality tipped-in color plates were popular starting in the late 1940s and into the 1980s.    Examples include several large series of books on painting published by Editions d'Art Albert Skira, Geneva: e.g. Painting, Color, History (23 volumes 1949-1972); The Great Centuries of Painting (14 volumes 1950-1959); The Taste of Our Time (57 volumes 1953-1972) with "hand-tipped colorplates"  Harry N. Abrams, Inc., Publishers, New York also published many fine art books during this period with tipped-in plates, examples include the 56 volume series The Library of Great Painters published 1959-1985 with each book having ca. 48 "tipped-on colorplates"  or "hand-tipped plates in full color". 
Typical uses of tipped-in pages added by the publisher include:
- color illustrations, generally printed using a different process (e.g. intaglio or lithography) and on different paper
- an author's signature, signed on a blank or preprinted page, before the book is bound
- original photographic prints
- maps, often larger than the book format and folded to fit
- coupons, advertisements, or reply cards
- errata sheets, only produced after the printing run
- a short addendum
- a replacement for a missing, damaged, or incorrectly printed page
Owners of books may also tip in such items as:
- a letter from the author
- a review
Tipped-in pages are generally glued to a bound page on its inner side and may be called "paste ins".
- "AbeBooks Glossary of Book Terms"
- Art: Perfectionist, Time Magazine, 29 May 1950. Accessed 27 September 2019
- Corisande Evesque. Albert Skira et ses livres d’art (1948-1973). Histoire. 2015. ffdumas-01256888
- Woodward, A. (updated 21 September 2019) Harry N. Abrams, Inc. encyclopedia.com. accessed 27 September 2019
- Courthion, P. (1956) Montmartre, volume 16 of The Taste of Our Time. Editions d'Art Albert Skira, Geneva. 143 pp
- Courthion, P. (1968) Seurat, The Library of Great Painters. Harry N. Abrams, Inc., Publishers. NewYork, 160 pp.
- Valcanover, F.; Pignatti, T. (1985). Tintoretto, The Library of Great Painters. New York, N.Y., USA: Harry N. Abrams, Inc., Publishers. p. 168. ISBN 0-8109-1650-9.
- Glossary of the International League of Antiquarian Booksellers, s.v. tipped-in