My kids (7,6,4 & 2) all love them. I think even the ones that are technically too young appreciate getting to color in the “special” coloring books, they just don’t seem too concerned about perfection and each color according to their ability even down to the two year old who basically scribbles :o)
I love that I can find a book on almost any topic/time period to reinforce what we are studying. I think I love them also because they are not “twaddle” like so many coloring books…..come to think of it I think that is probable why even my very young ones enjoy getting to draw in them, they don’t talk down to them but encourage them to participate in the family learning at their level.