It is not necessary to read Angels and Demons before The Da Vinci Code, as the two books are independent stories and do not directly tie into each other. While Angels and Demons introduces some characters who also appear in The Da Vinci Code, the events of the two books are distinct and can be understood without having read the other.
Reading Angels and Demons may provide some additional context and character background for certain elements in The Da Vinci Code, but it is not required for understanding or enjoying the overall plot. Both books can be read and enjoyed on their own without impacting the reader's comprehension or entertainment.