Our aims in bringing together the scholars assembled in this volume were threefold. First, we wanted to link a variety of research strategies and disciplinary vantage points in the human and social sciences in order to better understand the remaking-biological and clinical, economic and political, public and phenomenological-of the senile dementias today. Beyond the specificity of Alzheimer's disease or vascular dementia, many of us have been involved in research on what I have long termed senility. By senility, I mean the perception of deleterious behavioral change in someone understood to be old, with attention to both the biology and the institutional milieu in which such change is marked, measured, researched, and treated (Cohen 1998). For us, as social scientists and humanists of medicine, to organize our conversations around senility in this sense of the word, as opposed to organizing them around dementia, is simply not to presume in advance how perception, biology, and milieu are related. This reluctance to presume, as opposed to any shibboleth of naive social construction, is what makes us careful about terms and what makes our conversation anthropological. But far-ranging and systematic conversations among scholars of senility are few. Second, we presume that the future of senility, and clinically of the dementias, is an open one. Much is changing: state- and corporate-funded pharmaceutical, genomic, and epidemiological initiatives; instruments and regimes of health-care funding and insurance; structures and strategies of treatment and of care and their associated forms of reason; modes of therapeutic and nontherapeutic practice challenging the limits to such reason; differences and inequalities across axes of difference we attempt to capture by terms such as class, gender, race, and nation; and the larger frames of the structure of economies and institutions, generations and ethics, and bodies and persons. The perspective of the editors is not to presume that we understand what senility has been and must be-in the home, laboratory, clinic, chronic-care facility, regulatory office, or boardroom-and thus to offer an expert critique. It is rather to put our interpretive and critical tools to work to understand what senility might be becoming. In the case of the assembled chapters, our focus is on the dominant modern clinical form by which senility has been articulated-dementia-and what is happening to it. Finally, we presume that thinking about dementia is not only a salutary but also a necessary practice to address broader questions: of language, selfhood, and sovereignty; of the structure of care both in general and in the clinic; and of the practices and forms of reason and of life. That is, we hope to begin to reanimate the relation of senility to creative understanding in the human sciences more broadly, to move beyond the solicitous and welfare-driven categories of contemporary gerontology. We do not wish to claim that these chapters, or this introduction, singly or collectively accomplish all these objectives: such a claim would not do justice to the specific and contingent projects of the authors. But we do hope and expect that bringing these projects together will begin to suggest the contours of a field in the three ways we have outlined. Nor do we claim that we have been able to invite all or even most of the growing number of scholars thinking creatively about senility and dementia to participate in this volume. Our expectation is simply to frame a broader and more inclusive conversation. Both editors have in earlier or ongoing work focused on what the dementia clinic looks like beyond Western Europe and North America and share as well a sense of critical distinctions in the making and management of dementia within the so-called West. We have asked for contributions from authors who have been trained or are working or doing research in and across a variety of national sites (Brazil, Canada, Germany, India, Japan, the Netherlands, and the United States). The tools and theoretical commitments of these authors differ from one another and from those of the editors, and we have encouraged these contradictions in service of a robust conversation. The chapters in Thinking about Dementia are organized around a discrete set of problems, specific sites of the creative application of technical reason: (1) the emergence of new or reorganized forms of clinical practice in dementia given shifts in the dynamic of forces constituting clinical reality; (2) the role of genomics in Alzheimer's research and clinical practice, its reconstitution as a media object, and the popular reception and use of such media-driven understandings; (3) the organization of voice, self, or personhood in individuals with dementia across therapeutic and experimental milieus as well as the set of forces and forms that constitute both clinical and scholarly attention to "the person" with dementia; and (4) the relation between dependency and discipline in the constitution of senility as what Steven Collier and Andrew Lakoff (2005) have termed a regime of life. Before we turn to a preliminary engagement with each of these sets of problems, we offer some general reflections.