In Enid Blyton's bestselling series, the Naughtiest Girl and her friends make their own rules at their very unusual boarding school. In book eight, Elizabeth is desperate to play the piano in the end of school concert. Elizabeth knows Arabella is very good - so she spends every waking minute practising.

But exams are looming, and piano practice leaves Elizabeth with no time to revise. Will the Naughtiest Girl have to stay in First Form another year?Between 1940 and 1952, Enid Blyton wrote four novels about Naughtiest Girl, Elizabeth Allen. Books 5-10 are authorised sequels of the series written by Anne Digby in 1999.

Bonus material: A rare, complete serial story about a very special school. An interview with Enid Blyton about her school days. Enid Blyton's experiences as a teacher.

A timeline of the author's life. Photos from Enid Blyton's younger days.