Now I'm cross-correlating this with roleplaying sourcebooks, where the players and the GM are _expected_ to take what they want and then work with it, and encouraged to adapt it to suit the particular needs of the campaign. Cross out some characters, alter others, make a third into a secret spy or hired killer or romantic mushball, all for the needs of the mutual story being created.

Of course, the authors of the sourcebooks have to keep to the big book of canon, but all the readers are encouraged to take what they want and run with it. (I'm always quite pleased when I hear that someone's actually kept something that I wrote more or less as it was.)