Cambridge University Press and the University of California have forged an unprecedented open access agreement, including UC’s cost-sharing model for researchers with grant support and defaulting all UC authors into open access with an option to publish behind a paywall as appropriate. We’ll discuss the breadth of our cooperative partnership: the alignment of our goals and philosophies, the contours of the final agreement, the design of the author workflow and the handling of shared payments, and the collaborative efforts between Cambridge and UC to socialize open access with researchers across the 10-campus system.