As the first decade of Peanuts closes, Charlie Brown's sister Sally
makes her appearance -- first as an (off-panel) brand new baby for
Charlie to gush over, then as a toddler and eventually a real, talking,
thinking cast member. (By the end of this volume, she'll already start
developing her crush on Linus.) All this, and one of the most famous
Peanuts strips ever: "Happiness is a warm puppy."