Footnote

A footnote is a note of text placed at the bottom of a page in a book or document. The note comments on and may cite a reference for part of the main body of text. A footnote is normally flagged by a superscript number following that portion of the text the note is in reference to.


 * 1 for the first footnote on the page, 2 for the second footnote, and so on.

Occasionally a number between brackets or parentheses, is used instead, thus: [1]. Typographical devices such as the asterisk (*) or dagger (†) may also be used to point to footnotes. In documents like timetables, many different symbols, as well as letters and numbers, may be used to refer the reader to particular footnotes.

Endnotes are similar to footnotes, but differ in that rather than appearing at the foot of the particular page, they are collected together at the end of the chapter or at the end of the work. Endnotes are often considered more inconvenient than footnotes, as moving back and forth between the main text and the endnotes takes additional time and effort.


 * The U.S. Government Printing Office Style Manual devotes six pages to the topic.
 * NASA has guidance for footnote usage in its historical documents.

Academic usage
Footnotes are most often used as an alternative to long explanatory notes that can be distracting to readers. Most literary style guidelines (including MLA and APA) recommend limited use of foot and endnotes. However, publishers often encourage note references in lieu of parenthetical references. Aside from use as a bibliographic element, footnotes are used for additional information or explanatory notes that might be too digressive for the main text.

MLA requires the superscript numbers in the main text to be placed following the punctuation in the phrase or clause the note is in reference to. The exception to this rule occurs when you have a hyphen in a sentence, in which case the superscript would appear afterwards.

Aside from their technical use, authors use footnotes for a variety of reasons:
 * As signposts to direct the reader to information the author has provided or where further useful information is pertaining to the subject in the main text.
 * To attribute to a quote or viewpoint.
 * As an alternative to parenthetical references; it is a simpler way to acknowledge information gained from another source.
 * To escape the limitations imposed on the word count of various academic and legal texts which do not take into account footnotes. Aggressive use of this strategy can lead the text to be seen as affected by what some people call "footnote disease".

Footnotes as a literary device
At times, footnotes and endnotes have been used for their comical effect, or as a literary device.
 * Mark Z. Danielewski's House of Leaves uses what are arguably some of the most extensive and intricate footnotes in literature. Throughout the novel, footnotes are used to tell several different narratives outside of the main story. The physical orientation of the footnotes on the page also work to reflect the twisted feeling of the plot(often taking up several pages, appearing mirrored from page to page, vertical on either side of the page, or in boxes in the center of the page, in the middle of the central narrative).
 * Flann O'Brien's The Third Policeman utilizes extensive and lengthy footnotes for the discussion of a fictional philosopher, de Selby. These footnotes span several pages and often overtake the main plotline, and add to the absurdist tone of the book.
 * David Foster Wallace's Infinite Jest includes over 400 endnotes, some over a dozen pages long. Several literary critics suggested that the book be read with two bookmarks.
 * Manuel Puig's Kiss of the Spider Woman (originally published in Spanish as El beso de la mujer araña) also makes extensive use of footnotes.
 * Mark Dunn's Ibid: A Life is written entirely in endnotes.
 * Luis d'Antin Van Rooten's, Mots d’Heures: Gousses, Rames (the title is in French, but when pronounced, sounds kind of like the English "Mother Goose Rhymes"), in which he is allegedly the editor of a manuscript by the fictional François Charles Fernand d’Antin, contains copious footnotes purporting to help explain the nonsensical French text. The point of the book is that each written French poem sounds like an English nursery rhyme.
 * Terry Pratchett has made numerous uses within his novels. The footnotes will often set up running jokes for the rest of the novel.
 * Susanna Clarke's Jonathan Strange & Mr Norrell uses dozens of footnotes referencing a number of fictional books including magical scholarship and biographies.
 * Jonathan Stroud's The Bartimaeus Trilogy uses footnotes to insert comical remarks and explanations by one of the protagonists, Bartimaeus.

Opponents of footnotes
Associate Justice Stephen Breyer of the Supreme Court of the United States is famous in the American legal community for his writing style, in which he never uses footnotes. He prefers to keep all citations inline (which is permitted in American legal citation).