Just William

The Just William series is a sequence of thirty-nine books written by English author Richmal Crompton. The books chronicle the adventures of the unruly schoolboy William Brown.
Published over a period of almost fifty years, between 1922 and 1970, the series is notable for the fact that the protagonist remains at the same eleven years of age, despite each book being set in the era in which it was written. The first book was Just William, and often the entire series is named after this book. Each book, with the exception of the novel Just William's Luck, is a collection of short stories.
The series has spawned various television, film, theatre and radio adaptations. It also has a large fan following, with such groups as the Just William Society.