It was a vision in a dream. A computer filing system that would store and deliver the great body of human literature, in all its historical versions and with all its messy interconnections, acknowledging authorship, ownership, quotation and linkage. Like the Web, but much better: no links would ever be broken, no documents would ever be lost, and copyright and ownership would be scrupulously preserved. The Magical Place of Literary Memory: Xanadu. In this place, users would be able to mark and annotate any document, see and intercompare versions of documents side by side, follow visible hyperlinks from both ends (‘two-way links’) and reuse content pieces that stay connected to their original source document. There would be multiple ways to view all this on a computer screen, but the canonical view would be side-by-side parallel strips with visible connections (‘visible beams’). Just imagine. This vision – which is actually older than the Web, and aspects of it are older than personal computing – belongs to hypertext pioneer Theodor Holm Nelson, who dubbed the project Xanadu in October 1966.