Unique Coloring Books for Grown-Ups

Coloring is not just for kids anymore. Yahoo reported that two of the bestselling books on Amazon were coloring books. It's true that people of all ages love to color, and researchers suggest that coloring has calming effects on the mind and body. If you aren't quite ready to steal your kid's coloring books, we've rounded up a list of cool coloring books for grown-ups to try today!