This document provides an overview of the Copic marker color system and how to select colors that blend well together. It explains that each marker is labeled with a letter indicating its color family and numbers relating to saturation, tone, and darkness. Markers within the same color family that share the first number will blend most seamlessly. The document recommends choosing 2-3 colors that only vary in their second number to ensure consistent but varied blending. Understanding the color wheel and families will help select colors that naturally blend together for projects.