Strategy guides get released earlier and earlier these days so a lot of them lack information changed or added during the final stages of game development. A lot of them also lack information just because the strategy guide publishers want to release them before or at the same time the game is released. The strategy guide for Ninja Gaiden didn't even have all 50 scarabs listed. For competitive games, the guides are useless for multiplayer and the strategies they have are already obsolete in a week or two.