The Hooked On Phonics Achievement Cassette Series "20,000 Leagues Under the Sea" is a educational audiobook set intended for children and young adults aged 4-12. This series, published by Pendulum Press in 1993, includes a hardshell plastic case containing cassettes and paperback books. The stories included in this series are fiction narratives from authors such as Jules Vern, Charles Dickens, and William Shakespeare, with a focus on topics like adventure and Christmas. Each cassette and book set is designed to help young readers improve their literacy skills while enjoying engaging stories.