Bike Brain: Big Feelings and Regulation is a story about having big feelings and using movement to regulate. Rachel does not trust other people to help her regulate, and she has a lot of trauma triggers that cause dysregulation. Because she cannot co-regulate with another person, her foster mom suggests she go for a bike ride to help her calm down and recenter. The movement of the bike wheel spinning, the wind blowing in her ears, and the rapid repetition of pedalling help her heart slow and her breathing ease. Rachel does not like many things, especially being told what to do. When her foster mom suggests she wear her helmet and look out for cars, she is triggered, and her already bad mood becomes worse. She is forced outside by her own big emotions and desire to ride. She returns later with a smile on her face and regulated emotions. This is a great book for all children learning to regulate with movement or simply to understand what regulation is. Adults in the foster care world and therapists alike will appreciate the easy text and powerful lessons learned in this book. Brain Buddy teaches alongside the main story with trauma-centered brain science to help the reader understand why Rachel behaves the way she does and why movement is so beneficial to help her regulate her emotions. Rachel is a twelve-year-old and struggles with emotions, feelings, and regulation. In one image, the reader sees her throw a brick, expressing her huge feelings through a mighty dysregulated moment. Brain Buddy describes the stress response and why it is important to regain control of calm.