What is the difference between Digital Crayon Wisdom and Digital Crayon Books?

Digital Crayon Wisdom is the ideas: the library of explanations, the stories, the activities, the glossary, and the guidance for parents and teachers. All of it free and under no obligation to lead anywhere.

Digital Crayon Books is the product line: coloring books, activity books and project books by age band.

They are kept separate deliberately. A site trying to teach you something and sell you something in the same paragraph does neither well, and you can feel it in the writing.