The working definition
A prologue is a unit of narrative set apart from the main story in time, place, viewpoint or register, placed before the main story begins and labelled as apart, whose separation from Chapter One does work that the main narrative’s own opening pages could not do as well.
Each clause carries weight. Set apart in time, place, viewpoint or register names the four axes along which a prologue can differ from Chapter One, and a passage that shares the protagonist’s time, place and vantage and speaks in the book’s ordinary voice has opened no distance, whatever it is called. Placed before fixes the position: a separated unit after the main narrative is an epilogue or an afterword, and belongs with the ending. Labelled as apart is the clause most often forgotten, and it does the definitional work. A stylised, urgent opening scene is not a prologue because it is stylised and urgent; it is a prologue because the book has told the reader that it sits outside the main sequence. The last clause builds the chapter’s standard into the definition. A passage that could be folded into Chapter One with nothing lost was never a prologue, only an opening scene wearing a label its content did not need.
The definition is functional and typographic at once, on purpose. Some passages do a prologue’s work without the label: the opening chapters of Wuthering Heights (1847), in which the tenant Lockwood blunders into a story already nearly over, and the overture to Zora Neale Hurston’s Their Eyes Were Watching God (1937), a page of proposition about men, women and desire before the novel’s woman walks back into town. Others carry the label and do none of the work. Both kinds test the definition, and the tests in this chapter use both.
Two operations follow from the definition. Absorption folds a prologue’s material into Chapter One and deletes the label: a memory, a paragraph, a document the protagonist finds, a line of dialogue. Relocation moves the material to the point in the main timeline where it happened and lets it be an ordinary scene. Neither is a lesser form of deletion. Both keep good material and change only its compartment, and most prologues that fail this chapter’s tests should end in one or the other.
Length
No length is right in principle, and any figure offered is a convention. Prologues fall roughly into four sizes, and the size changes which failure is likely. An overture of a few hundred words, such as the Prelude to George Eliot’s Middlemarch (1871–72), risks doing an epigraph’s work under a prologue’s label. A scene of up to a few thousand words, the usual size of the commercial genre prologue, risks promising a more exciting book than the one that follows. A chaptered prologue of up to about ten thousand words, such as the four letters that open Mary Shelley’s Frankenstein (1818), risks reading as a first act, so that the reader never quite accepts Chapter One as the beginning. A sectional prologue beyond that, such as “The Custom-House” before Nathaniel Hawthorne’s The Scarlet Letter (1850), risks being skipped whole. One working rule, offered as a convention and not a finding: the longer the prologue, the earlier the book must begin closing the distance it opened, because a long prologue has borrowed more of the reader’s patience.
Adjacent terms
Several units sit near the prologue and are confused with it, and the confusions produce most of the bad advice. A cold open begins inside a scene already running and defers the framing. It is a way of starting, available to Chapter One as freely as to any separated unit, and nothing about beginning in motion requires separation: a cold open headed Prologue in the protagonist’s own time, place and voice is a Chapter One mislabelled. A preface is discourse about the text, addressed to the reader by an author, an editor or an invented intermediary, whereas a prologue is usually part of the fiction; the eighteenth-century novel blended the two, and the blend survives in the editorial notes of later books. A frame narrative is an outer story that contains the main one, and its first panel is often a prologue, but a frame returns and a prologue need not. An epigraph is a quotation placed at a threshold, which makes its claim by juxtaposition, not by telling. The teaser is television’s pre-title sequence and the nearest screen analogue, though on screen a cold open costs almost nothing, for reasons How It Works gives.
What this chapter leaves to others
The first pages of the main narrative belong to The Opening Pages (Chapter 9); a prologue precedes them and changes their conditions, since the reader of Chapter One has then met the book once already. Analepsis and prolepsis inside the running narrative, the flashback and the flash-forward, belong to Backstory and Flashback (Chapter 7), which applies this chapter’s language of distance to the cutaway. Chapter titles, part divisions and the other marks that segment a book belong to The Chapter Break (Chapter 6), which treats the prologue label as one member of that family. Epilogues and final notes belong to The Ending (Chapter 16). Which minds a novel may enter, and at what cost, belongs to The Viewpoint Shift (Chapter 13). The single late disclosure, considered for its own sake, belongs to The Reveal (Chapter 15), and the recap or prologue at the head of a series instalment to Series and Genre (Chapter 17).
See also: Reference definitions and boundaries, with a table of adjacent terms (the argument, the proem, the induction, the chorus, the dramatis personae) and the four sizes in detail.