The brains of a whole family are involved here: the psychiatrist: and neurologist who collaborated on The Human Body (1982) are now joined by their son as illustrator. In admirably manageable language, this ""Read-Alone"" packs in a lot: the brain is ""the most important part of your body. . .[it's] what makes you who you are."" Pointing out its irreplaceability (unlike even the heart), the Bruuns explain its content and size in terms kids can understand. Discussions of how neurons send messages, the relationship of the brain stem to the spinal cord, how other animals' brains work, and how some animals can search for food without a brain are included. Theories concerning intelligence, thought, emotions, sleep, and dreams are presented in a context of caring for the irreplaceable: thus, the brain merits protection from alcohol and drugs. Like the text, the illustrations here are simple and clear. Snappy side comments by onlooking birds add complementary humor to an informative, fascinating inside look at how we tick. Glossary.