1.   Eskridge, who wrote the introduction and explanatory material for the book, says the collection sheds new light on Mitchell.

2.   Indeed, she said, she rewrote the entire book six times to pare away explanatory material, to make the characters express their own reality.

3.   On second thought, it might be a good idea if the museum posts some sort of explanatory material, to avoid the inevitable embarrassing scenes.

4.   Parentheses contain explanatory material not included in the letter.