I Spy Shapes is a kindergarten book that teaches children about basic shapes like squares, circles, triangles, rectangles, rhombuses, ovals, and trapezoids. It shows examples of each shape and provides simple definitions, noting that squares have 4 equal sides and 4 corners, rectangles have 4 sides with 2 longer sides, and circles have a rounded edge without corners. The book encourages tracing and drawing ovals as practice identifying these common geometric shapes.