Mary Shepard, 90, who illustrated the Mary Poppins books for half a century, providing the whimsical nanny's style that was adopted for Julie Andrews in the 1964 motion picture. Mary Eleanor Jessie Shepard was born on Christmas Day in 1909, two years after her far more famous father, E.H. Shepard, had sold his first cartoon to the humor magazine Punch. In 1937, Mary married the editor of Punch, E.V. Knox. By then she had already launched her own modest career in collaboration with P.L. (for Pamela) Travers, author of the 1934 "Mary Poppins" and all its sequels. Travers had wanted Mary's father, who by then had illustrated "The Wind in the Willows" and the Winnie the Pooh stories. But E.H. Shepard was too busy to oblige. Then Travers saw a hand-drawn Christmas card she liked. It was by Mary Shepard, then 23 and just out of the Slade School of Art. Travers imagined the nanny looking like a doll she pulled out of the attic: a wooden peg Dutch doll with painted black hair and turned-up nose. Shepard bought a similar doll to pose by her drawing board as she made line drawings for the eight Mary Poppins books published from 1934 through 1988. The Disney motion picture somewhat changed the period of the story, but adapted Shepard's costume and style for Andrews' character. The author and the artist had many discussions of what the "almost perfect" nanny was to look like--including whether her feet would be in the ballet fifth position as a straight line or fourth position at right angles. The author won in the book versions where Mary's feet are at right angles; but the artist won out in the movie, where Poppins' feet are heels together at a 180-degree angle. Picking up where her father left off, Shepard illustrated A.A. Milne's lesser-known story "Prince Rabbit and the Princess Who Could Not Laugh" in 1966. On Sept. 4 in London.