Strategy guides should not exist in the form they seem to currently.

Thus I've never bought one.

A strategy guide should be just that. A guide to strategy.
But all too often they are effectively the manual & the game itself comes with merely a quickstart guide.

With all that CA has been making of the ingame help, a strategy guide for Rome should be more or less reduced to a real strategy guide & thus not useful to a Shogun/Medieval veteran.