The word prologue derives from pro - "before" + logos - "discourse, speech" and it is a preface or introductory part of a discourse, poem, or novel, so its function is to introduce some topics.

The prologue of "The Hours" presents Virginia Woolf's suicide. The story is setted in 1941, at the beginning of the World War II. The novel starts tragicly, with a person committing a suicide because of her mental illness and it is setted during the war, so the reader cannot expect happy-end story, full of happiness. Also the suicide arouses the reader's curiosity and he is asked to imagine what comes afterward, why she do this, what reaction has her family, how they react after reading of the letters she left. All these questions asked by reader, push the reader to go on reading.