Like Gizmo stated: the devs do NOT make the strat guide... BUT: professional game guide writers who work WITH the developers do write the guides. These guys write dozens of guides (iirc Bethblog linked an interview with the longhair who wrote the FO3 guide before it released, and he had written 30+ guides) and for the few inaccuracies they end up putting in (many are using a beta build to write from) you can download PDF printable inserts for your guide to keep it up to date.
Everyone that's saying :INTERNET is right, it's certainly a good way to get the info... but I like a book when I am actively playing the game.... Something about having the weight of it in your lap, mabye little sticky tabs to organize it... call me old fashioned, but I'd rather go through a game guide than try to find the correct youtube walkthrough (1 of 65)...