This book is a brave use of metafiction, pointing to Virginia Woolf's creative process. To understand this better, perhaps it would help to know that after her death, Virginia Woolf's private diary was published, giving the artists of the world access to her creative process. Those diaries were then consulted and used to reverse engineer a prose story, The Hours, depicting the difficult dance between the artist and her feelings of despair, her use of literature as an outlet, and the effect her artistic decisions have on the real world.
The mechanism described is this: Virginia Woolf is honest with herself about her relationship to her environment. Being in the suburbs makes her want to blow her brain out and die. As an artist, she longs to be in the hubbub of the vibrant city, but her husband drug her out to these boring outskirts, like a noose around her neck. So, having become honest about this, she turns to the book and puts it into a novel, codifying her emotions in the life of the character. She contemplates suicide for her character, and in a way, that is a painful way of avoiding a dark question of Woolf's own life.
The mechanism is complete when Laura reads about Mrs. Dalloway, she doesn't encounter a suicide, but in her real life, she does. The pain of real life needs to be put into the literature, decides Virginia, and so she arranges a minor character's death, but not Mrs. Dalloway's. This is a minimalistic depiction of mercy, because Virginia Woolf has the authority to drive her characters out of their minds and to die at her hand, but by picking a different path, she executes mercy on herself, on her character and on her reader. The point is that if she had tolerated that despair within her, she might have spread the despair to her reader who may or may not handle it well.
