Kay Nielson was a golden-age Danish illustrator and was one of my favourite artists as I was growing up. His specialty is depicting Scandinavian fairystories and awakening the imagination of kids all over the world.. There is something about his works that steeps the watcher in a parallel universe of mythology, romanticism and magic. (A universe I'm not ashamed to still yearn for). His style is so delicate and yet so elaborate and detailed - almost art deco sometimes. He illustrated the Grimms Fairytales and the Arabian Nights, amongst others. You can see some of his other work here. I never tire looking at them. Sigh.
If you are looking for a book for your children with all his illustration in it, I have got this book (click on image below) and it is a source of total delight for my nieces and nephew. Only about $12 too, from memory.