"The golden age" of coloring books is believed to be 1960-s, because almost all characters were depicted in them, as well as some products (like Planter Peanuts or Campbell Soup)

Coloring appeared in the United States as part of the "democratization of art", inspired by a series of lectures by British artist Joshua Reynolds and the works of the Swiss educator Johann Heinrich Pestalozzi together with his student Friedrich Friedrick Frobel.

Simple Flower Coloring Page