Appearing on his computer screen at work one night, these words, the opening lines of the text adventure game Adventure, fill Jackdaw Acquerelli ‘with a great sense of well-being. Happiness flowed in its own small stream out of [his] chest and down into his typing digits.’ A computer programmer in Richard Powers's novel Plowing the Dark, Jackdaw is not the only person to have had this response. Adventure, created originally by Will Crowther around 1975 and modified by Don Woods in 1976, invited a whole generation to enter the digitally created world of caves, mazes, puzzles, story, gameplay and participatory culture that has indelibly altered our understanding of popular fiction. When the young Jackdaw first discovered the game he perceived it as a world of ‘pure potential’. Today, the world of digital popular fiction built on that potential is vast and constantly changing, a world without clear origins, definitions, or borders, with so many paths to follow, so many disparate artefacts and practices to collect and describe, that even the most intrepid critical explorer could easily get lost. In many ways there does not yet exist a defined field that would contain a ‘digital’ version of popular fiction; both the artefacts, or new fictional forms, and the critical tools defy traditional categories, crossing media and disciplines.