Well, apparently they were back then and still are today for people of all ages. People are making the adult coloring books bestsellers on Amazon! At the time of this writing, eight of the top twenty books on the bestsellers list, are coloring books for adults. There must be something behind this recent growth in interest.
The computer and the internet have opened an entirely new spectrum of coloring and drawing. Adults now make very sizable livings creating, drawing and coloring pictures for computer animation including video games, movies, commercials and items most adults would never consider, such as some high-quality information websites. With this option available as a full-fledged career for adults, it is no wonder that the tools and formats used in this style of artwork have carried down to children, albeit on a smaller scale.
I was picking out some coloring books for my friends children when she informed me that she would like to get a couple of books too. This is a 30 something year old woman. She then began picking out colored pencils as well with a gleam in her eye like a kid in a candy store. She couldnt wait to get home and start coloring in her new books. She picked Barbie Doll, princess type books and methodically chose what colors she would use for the first picture.