In 2018, a group of mostly European funders sent shock waves through the world of scientific publishing by proposing an unprecedented rule: The scientists they funded would be required to make journal articles developed with their support immediately free to read when published. The new requirement, which takes effect starting this month, seeks to upend decades of tradition in scientific publishing, whereby scientists publish their research in journals for free and publishers make money by charging universities and other institutions for subscriptions. Advocates of the new scheme, called Plan S (the “S” stands for the intended “shock” to the status quo), hope to destroy subscription paywalls and speed scientific progress by allowing findings to be shared more freely. It’s part of a larger shift in scientific communication that began more than 20 years ago and has recently picked up steam.