Copyright. Copyright law is often called the “metaphysics of the law,” as judges labor to decide whether one work is enough like another to constitute copyright infringement. Often this involves arcane legal tests that few people, beyond copyright lawyers, care to think about. But, most of us read novels, and when one writer says, “your novel is so similar to my novel that it infringes my copyright,” we think, “that’s not so hard, I can decide that!” And, when one of the books is The Da Vinci Code (ranked 44th in books at amazon.com two and one-half years after publication), the chances are good that you, patient reader, have read one of the books that was the subject of just such a case. To see how a New York federal district judge decided the case in which Lewis Purdue, the author of Daughter of God and the Da Vinci Legacy, accused Dan Brown, the author of The Da Vinci Code, of copyright infringement, click here.