Penny begins the novel with a historical prologue about the revival of Gregorian chant and older manuscripts that preserved the art form. Early musical notation was meant to show the singer the direction of pitch, “Guiding some unseen monk to raise his voice. Higher. Then holding. Then higher again. Hanging there for just a moment, then swooping and sweeping downward in a giddy musical descent” (2). In so doing, she establishes that Gregorian chant notation will be key to the forthcoming mystery. The novel is interested not only in music in the abstract but in the physical objects that represent it. Frère Luc obsesses over the Book of Chants, while the prior dies clutching a piece of his new chant manuscript.

Musical knowledge is a source of power for the monks—the order hides in part to protect their particular relationship to the chants, their recording of the chants generates money and prestige, and their ancient Book of Chants contains the origins of the genre and is thus a priceless artifact. The music is also the community’s life force—specially chosen by the prior for the order’s choir, many of the monks are at Saint-Gilbert to emotionally heal.