What age is best for a first coloring book?

Most reviewers and parenting communities point to ages 1–3 for first coloring books with bold, thick outlines and simple shapes (like 'The Creative Toddler's First Coloring Book'), then 3–6 for character-driven books and 4–8 for activity hybrids with mazes and word searches. Older kids (8+) typically outgrow simple outlines and move toward more detailed designs.