Tales of a Fourth Grade Nothing was written by Judy Blume in 1972.
It is the first of the "Fudge books," followed by Superfudge and Fudge-A-Mania. All of the Fudge books follow Peter Hatcher, his little brother Fudgie, baby sister Tootsie, their neighbor Sheila Tubman, various pets, and minor characters through New York City and on treks to suburbs and camps.
Tales of a Fourth Grade Nothing is the first of these entertaining yarns. Peter, because he's the oldest, must deal with Fudgie's disgusting cuteness, his constant meddling with Peter's stuff, and other grave offenses.