Body text is the text forming the main content of a book, magazine, web page or other printed matter. This is as a contrast to both the headings on each page, and also the pages of front matter that form the introduction to a book.
Body text has two slightly different meanings, depending on context. A book designer, concerned with the overall sequence of a book, regards it as those pages that form the majority of a book, containing the body of text or body matter. A typesetter concerned instead with the layout of text on a page sees 'body text' as being those sections of the main text that are flowed into columns or justified as paragraphs, as distinct from the headings and any pictures that are floated out of the main body.
The 'body matter' is the group of pages that contain the body of the text of the book. The front matter comes before it, containing title pages, content lists, publisher's metadata etc. It is followed by the back matter, which includes appendices, references, credits, colophon etc. The distinction between the parts, body and other, is that the body matter is produced by the author, the front and back matter by the publisher (through the book designer, index collator etc.). Where there is a prose introduction, it demonstrates this; an introduction by the author is considered as body matter, an introduction by an editor or other commentator is placed with the front matter. In some technical publications, appendices are so long and important as part of the book that they are a creative endeavour of the author, rather than a mere collation exercise by the publisher. In this case they may, like the introduction, be considered as a part of the body matter.
At one time, books were produced as 'letter-books', where the body of text consisted of chapters of solid text, unillustrated. Where illustrations were provided, these were costly and so plates were inserted in sections, either at the end of the body matter, or grouped within the signatures. Development in printing in the early 20th century, and particularly developments in newspaper design and the incorporation of photographs, encouraged the development of the 'picture-book' where images were mixed in the text and formed part of the body matter itself (although in most cases, this was still outside the paragraphs of the typesetter's body text).