It is a Hollywood truism that commercially successful films attract litigation. So do wildly successful works of literary fiction. Why do people sue against successful films and novels? Answer: usually, for a slice of the money.
Among the most successful books of our era is Dan Brown's The Da Vinci Code. A sequel to the 2006 Hollywood adaptation is in the production line.
Since 2004 The Random House Group Ltd, publisher of The Da Vinci Code in the UK, has had a dark cloud of litigation over its head in courts in England.
In the first court case, the court sat for 11 days hearing legal arguments as to why The Da Vinci Code allegedly breached copyright in The Holy Blood and The Holy Grail. In the US it was re-titled (Holy Blood, Holy Grail). I had a view on that case as soon as I heard the report that The Holy Blood is a work of non-fiction. More on that later.