I’d be very curious to know the reason for this progression toward linearity. Presumably the invisible hand was guiding this development, but whether the hunger was for less difficulty in the books or simply for something with more in the way of traditional storytelling is harder to unravel. I could also imagine that this balance between interaction and exposition was peculiar to the individual writers, so this could merely reflect a changing set of practitioners. In another way, this trend mirrors the adoption of more recent new media. In the early days of the web, people flocked to what was unique to HTML, namely links, animated gifs, and the <blink> tag. A similar cautionless exuberance marked the appearance of affordable typesetting systems – the first time people without phototypositors had access to typefaces beyond a choice of monospaced typewriter fonts.When a world of new possibilities has just opened, it’s hard to find the will for restraint. But, in time, people scale back the more gratuitous uses of this sort of glitz, moving from what’s possible to what best suits the material. It could be that the glut of choices in the early books reflected more a rush toward the new than a well-considered balancing of storytelling and reader-directedness. As the genre developed, the choice-based structure ceased being so novel that it was an experiential end in itself. Perhaps only then could it recede into its proper role as a gameplay mechanic – all the more potent when used judiciously.

a peek into the construction process the authors went through as they folded their nonlinear stories into a sequential medium

In a computer game, tracking this kind of inventory state is a simple matter. By flipping bits in memory, the program itself can keep a running tally of items you’ve encountered and possibly picked up. In a book this responsibility falls to the reader, and with it an expectation of honesty. To encourage a degree of fair play, the Cavern of Doom engages in a form of entrapment by asking the reader, in the midst of a dicy situation, whether they have a magic item that would clearly save the day. What the book knows and the reader may not is that this item does not even exist. Woe upon the adventurer who angers the gamebook in this way.