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.
Considering the importance of different shades in the lives of people, adult coloring books have been brought into the market. Portable coloring books are one step ahead; adults can carry such products wherever they want to. Following are the top five benefits of such things: Light in weight: The best thing about such books is that they are extremely light in weight, thanks to which you can carry them to all the places you want to. They are never added luggage to you.