What strikes me now as an adult are the pictures which illustrate a very traditional family - one boy and one girl (the girl in pigtails, skirt and blouse), one dad (in suit and tie) and one mom (with an apron and mop in hand). The story itself is fun and timeless, though some of the ways that Harry gets dirty - sliding down a coal chute - and the illustrations are reflective of the times (the book was originally published in 1956).
The language is mostly timeless, though the use of the words “mummy” for “mommy” and “scrubbing brush” seem a little outdated to me. There were several Harry books published, but this is the one that I always remembered and associated with Harry. I always thought of Harry as the little dog who loved to get dirty and who hated to take a bath, something that I think is universal and that children continue to relate to, even to this day.