Among the defining characteristics of fourteenth- and fifteenth-century Northern European manuscripts is the trend for grisaille, a technique of rendering images primarily in tones of gray, black, and white. Grisaille miniatures take many forms: sometimes figures in gray appear against full-color backgrounds; sometimes an entire scene is rendered in complete monochrome or with sparse applications of gold leaf; and occasionally areas of color and gray are not neatly delineated but overlap in complex ways. This dissertation explores how grisaille embodies meanings, how it signifies, in order to understand its particular representational mode. I focus on grisaille in Burgundian manuscripts, especially those made for Duke Philip the Good and his courtly milieu by some of the most renowned miniaturists of the period. Grisaille in these manuscripts does not conform to one set of representational rules and cannot be interpreted along strict iconographical lines; its function is neither steadfastly hierarchical nor chronological. Instead, grisaille is a multivalent visual language. It expresses meaning through comparison with color, as a non-color, an anti-color, or the stripping away of color, and this rupture, this deviation from naturalism, creates an inherent effect of otherness and distance that can function in various ways. It can act, for example, as a path to unknown experiences and higher truths, as a shift in representational levels of reality, as a reminder of the artistic act of creation as well as the act of viewing, as a marker of personal status, and as an aid to devotion.