At the beginning of the 21st century, breathtaking changes in technology are posing stark challenges to our constitutional values. From free speech to privacy, from liberty and personal autonomy to the right against self-incrimination, basic constitutional principles are under stress from technological advances unimaginable even a few decades ago, let alone in the founding era. This means that scholars need to begin thinking about how constitutional principles are being tested by technological change and how to ensure that those principles can be preserved without hindering technological progress.

Consider questions such as the following:

• Is the Fourth Amendment obsolete in an age of ubiquitous cameras and unlimited data storage and processing, or can the law somehow restrict surveillance without crushing innovation? 
• How vigorously should society respect the autonomy of individuals to manipulate their genes and design their own babies? 
• How can we protect free speech in a world in which Google and Facebook have more control over who can speak and be heard than any government or judge? 
• In a world in which biologists can create organisms with large quantities of human genetic material and computer scientists can build machines with human intelligence, how will we define "person" for purposes of citizenship and constitutional rights?
• Can we plausibly and in a fashion consistent with our constitutional values protect security in a world of pervasive dependence on internationally networked computers and in which individuals all over the world can manufacture biological weapons?

The project of keeping the Constitution technologically current is not new. The most creative constitutional thinkers have long struggled to adopt constitutional values to changes in technology. Courts, legislatures, and citizens have long struggled with the obsolescence of law—including constitutional law. And depending on the laws in question, they take widely differing approaches. Sometimes, provisions of the Constitution fade harmlessly into anachronism. In other instances, courts have endeavored to keep doctrine technologically current. Sometimes, Congress and regulatory agencies have kept constitutional values current by supplementing the text itself with legislation or regulation. And sometimes, keeping the Constitution up to date requires actually updating the constitutional text itself.

In this series, a dozen scholars of diverse political and jurisprudential world views were asked to imagine plausible technological developments in the year 2025 or so that will stress current constitutional law and to propose possible solutions. Some them addressed issues that are certain to arise in the near, almost imminent, future. Some addressed issues that are more speculative and hypothetical. Some favor judicial responses to the scenarios they pose; others prefer legislative or regulatory responses. Individually and collectively, the essays present an invaluable roadmap for responding to challenge of adapting our constitutional values in the 21st century.