"A gamebook is a book that allows the reader to participate in the story by making choices that affect the course of the narrative, which branches down various paths through the use of numbered paragraphs or pages." --Wikipedia
Name variations: Choose your own adventure, CYOA
The first video game about Gamebook was released in 1980.
* Run away, deeper into the caves --- go to page 76
* Draw your firelance and shoot it --- go to page 73
* Hide in a nearby crevice --- go to page 82
Original gamebooks were like this, books that emulated a very basic game in form of a branching story. Very simple to device as they're effectively a large number of almost completely unrelated events. Usually with a very large number of endings with no clear "true" ending unless there is a sequel (usually there wasn't).
One popular series of gamebooks was named "Choose your own adventure" hence why many Americans call them that.