I was under the mistaken impression that this book contained the full play....not so! My fault as I clearly did not read the description properly.
This turned out to be an excellent mistake as I was looking for all I could find on Twelfth Night as I will be directing the play in a few weeks time.
From a directors point of view York Advanced Notes are a terrific source of information. It dissects each character in some depth, takes the reader through each act, discusses characterisation, themes and breaks down the sometimes difficult language into manageable words and phrases.
The copy I bought has also been quite heavily annoted by it's previous owner which should have been a sign for me to tear my hair out and demand a refund. These notes however, have been almost as useful as the book!
I would certainly recommend York Notes to directors, actors or students wanting to "really" understand Shakespeare