I bought this for my 7 year old grandson who loves drawing cars, tanks, planes etc. I like it because it gives clear, simple steps for a child to follow and I would say it is well suited to the 5-8 years' age group or earlier if your child is more artistically able.
The only reason I did not give it 5 stars is because I think it could be made a bit more modern looking, not just the cover but also some of the content. It needs a bit of an overhaul to make it perfect but in terms of drawing guidance it is great. I think there might even be a newer version so just check that out before you order.