The Mikado is the ninth of the 14 Gilbert and Sullivan musical collaborations. It opened in 1885, had the second longest run for any work of musical theatre of the time, and remains the most frequently performed Gilbert and Sullivan. It was adapted as a children's book by W. S. Gilbert entitled The Story of The Mikado, which was Gilbert's last literary work (and published posthumously). It is a retelling of The Mikado, with various changes to simplify language or make it more suitable for children.

This is that children's book. No singing or any of Sullivan's music, just Gilbert's witty words laid out - by him - in prose and poetry with amusing asides.

The Forward mentions some illustrations by Alice B. Woodward in the hardcopy, and they are lovely. They can be seen by following the e-text link to the actual scanned book if you wish.

(Summary by Wikipedia and ToddHW)