Scholars and judges have long debated whether antitrust law requires dominant firms to share so-called “essential facilities” with rivals. In her final paper, the late Professor Suzanne Scotchmer and co-author Stephen M. Maurer argue that the doctrine should return to its historic focus on industries where sharing promises important—and otherwise unachievable—synergies. They explain how a reformed doctrine can codify this principle and still be consistent with the existing case law. Their analysis is particularly relevant to the digital economy where rivals routinely use the same shared networks, platforms, and interoperability standards.