Let me start by saying I love Roberts Lawson's illustrations; I always have. He excels at black and white drawing, of placement of lights and darks on the page. He illustrated for St Nicholas, and for adult magazines of his day. Most people know his artwork from Munro Leaf's Ferdinand the Bull or Mr. Popper's Penguins, by the Atwaters. During his career he was called on to illustrate the writings of Dickens, Twain, Coatsworth, as well as classics like One Foot in Fairyland, by Eleanor Farjeon and The Sword in the Stone, by T H White.
If you are only familiar with the Disney version of this historical fantasy, you'll be greatly surprised by the differences.