Douglas Adams & Gareth Roberts 
Doctor Who: Shada 

The legendary lost Doctor Who story from the unique mind of Douglas Adams
Inside this book is another book – the strangest, most important and most dangerous book in the entire universe.
The Worshipful and Ancient Law of Gallifrey is one of the Artefacts, dating from dark days of Rassilon. It wields enormous power, and it must not be allowed to fall into the wrong hands.
Skagra – who believes he should be God and permits himself only two smiles per day – most definitely has the wrong hands.
Beware Skagra. Beware the Sphere. Beware Shada.