This volume represents the first collection of essays on the subject of eruv that combines the halakhic, historical, sociological and artistic aspects of this age-old rabbinic innovation. In the past several decades, the eruv has caught the attention of scholars and artists, sociologists and politicians. Historians have begun to study the development of the eruv from the courtyards of Roman Palestine to the urban eruvin of the modern period. How did the walls and gates of the early period evolve into the ''virtually invisible'' lines of the modern period? How does the history of the eruv inform an understanding of the history of Jews in cities and towns throughout Europe and the Muslim world? Furthermore, in the twentieth century, how does the eruv contribute to the appreciation of the development of Orthodoxy in America and modern-day Europe? Several historians grapple with these issues and attempt to weave the eruv into the fabric of the history of Jewish communities and cultures. For artists, the ability to imagine ''virtually invisible'' lines as solid walls creates endless opportunities to delve into the worlds of the imaginary and the real and the relationship between the two of them.