With his first George and Martha book, James was already entirely himself. He lacked only one component in his constellation of gifts: he was uncommercial to a fault. No schticking, no nudging knowingly, no winking or pandering to the grownups at the expense of the kids. He paid the price of being maddeningly underestimated – of being dubbed "zany" (an adjective that drove him to murderous rage). And worse, as I saw it, he was dismissed as the artist who could do – should or might do – worthier work if he would only dig deeper and harder. The comic note, the delicate riff, were deemed, finally, insufficient. James knew better, of course, and he was right, or course, but he suffered nevertheless. There was nothing he could do to impress the establishment; that was his triumph and his curse. Marshall did fulfill his genius, and its rarity and subtlety confounded the so-called critical world. The award givers were foolish enough to consider him a charming lightweight, and when Caldecott Medal time came around, they ignored him again and again.
– the foreword written by Maurice Sendak from George and Martha: The Complete Stories of Two Best Friends by James Marshall