In the United States nearly 40,000 people die annually as a result of being shot by a firearm. Another 73,000 people experience firearm injuries — some so severe they are life altering. There is no question that deaths and injuries from firearms — what we will call gun violence — comprise a serious and important problem in this country. It is also evident that the United States has long resisted solutions to its gun violence epidemic. The reasons for the seeming intractability of our ability to staunch the flow of gun violence are varied. There is not just one gun violence problem in the United States, and there is no single solution.

From 2019-2020, members of the Yale University community, working with scholars, physicians, advocates and other experts from across the country sought to address the issue through the tools of inter-disciplinary conversation and research. The twentyseven articles that resulted, which comprise this issue, engaged three framework questions:

• What exactly is America's gun violence problem, and do the policy response fit the real causes?;

• How is the criminal justice system, and its stake-holders, responding to gun violence?; and

• How has the law conceived of the nature of gun violence and the constitutional issues concerning gun safety regulations?

Our approach was intentionally interdisciplinary to bring together perspectives and methodologies that are not always in dialogue with one another. The articles put medical practice in dialogue with legal doctrine; sociological approaches in dialogue with criminal justice; empirical study in dialogue with constitutional law. The papers loosely fall into four categories, but all are in conversation: (1) criminal justice, (2) medicine and public health, (3) the roles of regulation and litigation, and (4) data and empirics.

In the context of criminal justice, the authors in the volume use various methodologies to critique the status quo and propose new methods to address gun violence. An important theme is community engagement. One article analyzes police interactions with gun violence victims, calling for a checklist system for law enforcement to follow in the aftermath of gun violence to ensure community needs are attended to; a second utilizes interviews of law enforcement and non-law enforcement partners involved in a group violence intervention (GVI) program to illuminate best practices for implementing GVI strategies; a third details community-endorsed strategies that give those affected by gun violence the resources to address it within their own communities.

With respect to health, in addition to examining public health approaches, the pieces focus on a full spectrum of issues related to health and the practice of medicine as related to gun violence. Authors discuss stigma and mental health; the costs and benefits of expanding the use of extreme risk protection order laws (ERPOs); the role of guardianship laws as a complement to EPROs in reducing gun violence; patterns of gun purchasing during the COVID-19 pandemic; whether gun violence can be addressed, with a medical lens, through a behavioral addiction model; the effects on health care providers treating patients in a mass casualty; and prevalence of youth emergency department visits due to gun violence. Contributors also took on challenging issues of understanding the roles of healthcare providers in gun policy, and the extent to which gun violence prevention laws inform clinical practice. One article empirically investigates psychiatrists' understanding of the gun ownership consequences of voluntary, involuntary and emergency hold admissions; another details how legal regimes, sometimes unknown to doctors and differing across states, provide a spectrum of responses available to physicians facing high risk patients; another unpacks physicians' ethical obligations to their patients and to the public to address the gun violence epidemic.

The third category that developed from our framing is understanding the roles of two legal mechanisms to address the gun violence problem outside of criminal justice: litigation and regulation. Regulatory gaps — often intentionally created by Congress — have led advocates to look to litigation as a salve. As one paper details, Congress granted the gun industry exceptional, and perhaps partially unconstitutional, tort immunity in the controversial 2005 statute, the Protection of Lawful Commerce in Arms Act. Another compares federal regulation of guns to the much stronger regulation tobacco, especially as it pertains to youth access. Another maps decades of affirmative litigation against gun violence, examining how and why gun litigation has not been as successful as public health litigation in other areas, like opioids.

Of course, the legal dimensions of gun violence throughout the volume are addressed against the back-drop of a robust discourse of constitutional law. Authors critique efforts to use the Second Amendment as a basis for so-called Second Amendment “sanctuary cities” — as well as efforts to use the Second Amendment, during COVID-19, to protect access to guns in the face of other closures. They consider open questions in constitutional doctrine about how to regulate new technologies, such a ghost guns. They discuss how to design extreme risk protection laws that ensure due process rights are protected, and argue that the Second Amendment, like the First, should not be read to protect those who threaten unlawful violence. And they advocate for a new kind of constitutional discourse in defense of gun regulation, more broadly focused on broad array of constitutional rights protected by the absence of gun violence.

Finally, we illustrate the pressing need for empirical evidence. There is a marked gap in the understanding of gun violence, specifically what existing data says about the nature of the problem and how policy responses map onto those problems. One article identifies the data gaps that remain and proposes that states evaluate the gaps in their systems, expand data collection, and improve data presentation. Survey data can inform policy too. A representative survey of 2000 Americans reveals broad support for a legal default rule against visitor possession of guns on private land — the opposite presumption of current law in many states. Another piece illustrates the power of corporate leadership in addressing gun violence by empirically estimating that Walmart's choice to stop selling handguns likely avoided thousands of gun suicides. Authors also present new empirical data illustrating the efficacy of licensing regimes as effective and politically palatable tools of regulation.

Each election cycle brings with it roadmaps for the future on key issues, and gun violence is no exception. Regardless of the outcome of the 2020 election, the gun violence problem is not going away. The multiple perspectives in this volume reveal the benefits of an “all hands on deck” approach to addressing this important public health problem, its many victims, and its future.