The "Mr. Men and Little Miss Series" is a popular collection of children's books created by Roger Hargreaves. The series features a variety of colorful characters, each with distinct personalities and traits, such as Mr. Happy, Little Miss Sunshine, and Mr. Grumpy. These characters often find themselves in humorous situations that teach valuable life lessons. First published in 1971, the series has expanded to include over 40 titles, along with merchandise, animated adaptations, and spin-off series. The simple illustrations and engaging stories make the books appealing to young readers, encouraging them to explore themes of friendship, kindness, and individuality.