Beatrix Potter. Obviously.
I remember getting a collection of Beatrix Potter stories and illustrations when I was about seven or eight. I practically ate the thing. I loved it, it was so magical. Her style of illustration is the perfect blend of scientific and believable, and whimsical and relatable. Which I think is a hard combination to get right. I never noticed that mice cannot wear clothes and it never occurred to me that hedgehogs do not make tea.
I bought it. I bought it all.
I still do.
Born in 1866, Beatrix Potter never experienced all the animated and illustrative popular culture that we do now, and even I in my modern, fully-realized, well-informed pool of reference cannot master the powerfully simple and impossibly timeless illustration that she breezed through as if she invented whimsy itself.
Her scientific education and silly childhood imagination have come together so perfectly and delightfully that I have decided that you (readers,) must become more familiar with her work.
Here is a link to a specific page in her dedicated website, showing her chops as a story-teller and lover of nature.
Everyone, take a moment to appreciate childhood.