Who created the Arthur book series?

Marc Brown created the Arthur book series.

Brown is an American author and illustrator who wrote and illustrated the original Arthur books. The character began in the 1976 picture book Arthur's Nose, published by Little, Brown and Company. That story introduced Arthur as an anthropomorphic aardvark whose unusual nose makes him self-conscious.

The book series grew through stories about childhood, family, school, friendship, and everyday problems. Arthur's appearance changed over time: early illustrations gave him a more realistic aardvark-like snout, while later books and the television adaptation used the familiar shorter-nosed design and round glasses.

The animated series was developed from Brown's books, but Brown was not its sole television creator. Kathy Waugh also helped develop the show, and WGBH and CINAR produced it. That distinction explains why Marc Brown is the correct answer for the book series, while the television program had a broader creative and production team.