Crowds are a ubiquitous feature of everyday life. People have long assembled collectively to observe, to celebrate, and to protest various happenings in their everyday lives, be they natural events, such as a solar eclipse, or the result of human contrivance, such as the introduction of machinery into the production process. The historical record is replete with examples of crowds functioning as important textual markers, helping to shape and define a particular event, as well as strategic precipitants and carriers of the events themselves. The storming of the Bastille and the sit-ins and marches associated with the civil rights movement are examples of crowds functioning as both important markers and carriers of some larger historical happening. Not all crowds function so significantly, of course. Most are mere sideshows to the flow of history. Nonetheless, the collective assemblages or gatherings called crowds are ongoing features...