Roy Porter, the historian of Western medicine, once wrote that "the historical record is like the night sky: we see a few stars and group them into mythic constellations. But what is chiefly visible is the darkness" (1997, 13). Florence Bretelle-Establet, the editor of this volume, offers a different metaphor, one that has primary sources flashing by like trout. ' "Upstream from the historians' act of composing a corpus and dealing with sources, " she writes, "a great variety of actors imposed their goals and values on the material and social life of documents" (xxxiv). This ecological metaphor is even more apt than Porter's. Both emphasize that what ends up in the historian's constellation or bucket reflects the direction of her gaze and her own skill at observation and capture. But Bretelle-Establet's imagery makes it clear that the specific fish darting by in her part of the creek are not random or natural, like the specific stars occupying one corner of the sky. Rather, their distribution reflects the damming, culling, and selective propagation that others have done before us. Some texts have been deliberately suppressed and destroyed through censorship, while others have been preferentially collected and preserved. Before a modern historian ever has the opportunity to impose his categories and biases on extant primary sources, a seventh-century commentator, a tenth-century compiler, and an eighteenth-century Western scholar may already have determined what was available.
