The book is noted for portraying one of the first non-caricatured African-Americans in a major children's book.
In the book, Peter, a little African-American boy living in Brooklyn, wakes up to a snowy day, puts on his red snowsuit and goes outside with "a stick just right for knocking snow off of trees, and a snowball in his pocket."
What was so groundbreaking was that Keats, who was white, makes no mention of the fact that the character Peter is African-American. It is only discerned through the beautiful illustrations.
"It was no longer necessary that the book say, 'I am an African-American child going out into the snow today...you don't put a color on a child's experience of the snow," Deborah Pope, executive director of the Ezra Jack Keats Foundation, told NPR.
Keats was born in 1916 to poor Polish Jewish immigrants in the East New York section of Brooklyn. He graduated from Thomas Jefferson High School and before that attended Junior High School 149, where he won a medal for his artistic talents upon graduation. He kept the medal all his life, together with the prestigious awards he won in his later career, such as the Caldecott Award, which he won for "The Snowy Day."
You can read more about Keats here.