Industries of production and scientific research rely on the use of nonhuman animals and plants, remaking environments, populations, and even genetic information to suit human designs. This issue of Social Text considers the radical implications of questioning the exceptional status of humans among the planet's species. Responding to growing interest in animal studies and posthumanism, the contributors draw on racial, feminist, queer, postcolonial, and disability theories to probe the diversity of human relationships with other forms of biosocial life. Interspecies queries the politics of traditional species taxonomy and examines the ways humans use the material characteristics of other species to pursue their economic, political, and social aims. This collection goes beyond companionate species to examine less charismatic life forms: viruses, vermin, transgenic pigs, and commodified plants. Bringing together prominent scholars and artists from a range of fields, the issue examines the histories of species collection and display. In the context of current public health challenges, including the swine flu epidemic and the scarcity of donor organs, the contributors explore the limits of transgressing species boundaries that arise when human bodies contain other species, such as viruses or transplanted organs from genetically customized pigs. Interspecies analyzes the use of nonhuman species in the biopolitics of warfare and torture and examines how interspecies relationships shape conditions of colonialism, imprisonment, and violence. The issue also complicates romanticized narratives of human/nonhuman animal dynamics without resorting to oversimplified portrayals of human exploitation of animal and plant life. Julie Livingston is Associate Professor of History at Rutgers University. Jasbir Puar is Associate Professor of Women's and Gender Studies at Rutgers University. She is the author of Terrorist Assemblages: Homonationalism in Queer Times.