I had to read this for work in order to update our in-house style manual. I can't say it was the most exhilarating text, but it was interesting to see behind the curtain of the news I read on a daily basis - and to get some nice definitive answers regarding grammar to use on the job.
This is a very good and authentic tool for copy editors, and it was required for my copy editing course. I always refer to it whenever I am not sure about the use of punctuation and stuff like when to use spell out numbers and when not to.