A sketch is typically a preliminary drawing made to explore ideas, compositions, and character designs before the final art is created. In the context of children's books, sketches serve as an important step in the illustration process, allowing artists to visualize scenes and experiment with layouts. These rough drawings can convey motion, emotion, and interaction between characters, helping both illustrators and authors refine their visual storytelling. Ultimately, sketches play a vital role in shaping the final look and feel of the illustrated work.