Open access: All human knowledge is there—so why can’t everybody access it?

Imagine, for a moment, if it were possible to provide access not just to those books, but to all knowledge for everyone, everywhere. In fact, we don't have to imagine: it is possible today, thanks to the combined technologies of digital texts and the Internet. The former means that we can make as many copies of a work as we want for vanishingly small cost; the latter provides a way to distribute those copies to anyone with an Internet connection. The global rise of low-cost smartphones means that "anyone with an Internet connection" will soon include even the poorest members of society in every country. We have the technical means to share all knowledge, and yet we are nowhere near providing everyone with the ability to indulge their learned curiosity.

What's stopping us? That's the central question that the "open access" movement has been asking, and trying to answer, for the last two decades. Although tremendous progress has been made, with more knowledge freely available now than ever before, there are signs that open access is at a critical point in its development, which could determine whether it will ever succeed.