Hanger is the emotion you feel when you're angry and hungry at the same time. It can be caused by not eating enough, eating too much, not getting the right nutrients, etc. The result is irritability, high emotions, and lashing out. This book seeks to define hanger, why it happens, and how you can prevent it. This sounds interesting, relatable (who hasn't been hangry before?), and enjoyable for those who like reading self-help books.