“Interoperability” is the act of making a new product or service work with an existing product or service: modern civilization depends on the standards and practices that allow you to put any dish into a dishwasher or any USB charger into any car’s cigarette lighter.

But interoperability is just the ante. For a really competitive, innovative, dynamic marketplace, you need adversarial interoperability: that’s when you create a new product or service that plugs into the existing ones without the permission of the companies that make them. Think of third-party printer ink, alternative app stores, or independent repair shops that use compatible parts from rival manufacturers to fix your car or your phone or your tractor.

Adversarial interoperability was once the driver of tech’s dynamic marketplace, where the biggest firms could go from top of the heap to scrap metal in an eyeblink, where tiny startups could topple dominant companies before they even knew what hit them.

But the current crop of Big Tech companies has secured laws, regulations, and court decisions that have dramatically restricted adversarial interoperability. From the flurry of absurd software patents that the US Patent and Trademark Office granted in the dark years between the first software patents and the Alice decision to the growing use of "digital rights management" to create legal obligations to use the products you purchase in ways that benefit shareholders at your expense, Big Tech climbed the adversarial ladder and then pulled it up behind them.

That can and should change. As Big Tech grows ever more concentrated, restoring adversarial interoperability must be a piece of the solution to that concentration: making big companies smaller makes their mistakes less consequential, and it deprives them of the monopoly profits they rely on to lobby for rules that make competing with them even harder.

For months, we have written about the history, theory, and practice of adversarial interoperability. This page rounds up our writing on the subject in one convenient resource that you can send your friends, Members of Congress, teachers, investors, and bosses as we all struggle to figure out how to re-decentralize the Internet and spread decision-making power around to millions of individuals and firms, rather than the executives of a handful of tech giants.