I'm not sure why the comparison between computer games and gamebooks was added. I'm actually kind of surprised it's lasted this long and been edited instead of just being whacked. I'm +1 for removing the following two paragraphs: 

 A noticeable difference between gamebooks and computer games is that by the very nature of their physical format (i.e. being a book), reading a gamebook allows you to retrace your steps and do things you overlooked. Computer programs, on the other hand, must be specifically programmed to accomplish retracing and backtracking, with the result that for most computer games the only way to change a decision once made is by restarting the game. Some computer games, including electronic game books, do allow you to "undo" your progress, sometimes in a way meant specifically to simulate how you read a physical gamebook.Unlike a computer game (where the computer handles things for you) a gamebook requires external implements (such as a paper and pencil or figures... or merely all your ten fingers) to keep track of changes that the player makes to the state of the game. Many gamebooks offer a reduced form of state change by having the user keep an inventory of items that unlock certain branch points, but most do not, so most branches can only be visited once. 

 Neither paragraph has a single citation, they seem like original research (or something similar) and I'm not sure if the best way to describe gamebooks (or anything for that matter) is the format "A noticeable difference between x and y."