Today’s Please Explain is all about breakfast cereal. Food historian Andy Smith, the author of Eating History: Thirty Turning Points in the Making of American Cuisine, among other books, joins us along with Edwin Chavey, aka Mr. Breakfast, director of the Mr. Breakfast Website and "The Cereal Project," a database of 1,200 cereals made in the United States, to explain what cereals are made of, how truthful health claims made about some are, and how there got to be so many varieties.