What's Up Jac? is a lively and charming picture book that likely features an animal character named Jac, perhaps a mischievous monkey or a curious young bird. The story uses a conversational title to suggest a narrative focusing on curiosity, communication, and possibly a mild predicament. Rob Lewis often creates engaging, dynamic illustrations that complement his simple, humorous text. The book probably follows Jac through a day of adventures or a simple misunderstanding, teaching a gentle lesson about friendship, perspective, or expressing one's feelings. It is designed to be a fun, interactive read-aloud with an easy rhythm that appeals to the preschool audience and promotes enthusiastic engagement.