Generations of children in Welsh medium schools have enjoyed the tales of mischievous farmyard animals, especially the antics of a duckling and fox in Llyfr Mawr y Plant (The Big Book for Children).
Now their adventures have been turned into a musical, which is already proving a hit with teachers.
But according to the man who revived the famous Welsh language children's book a decade ago, it will continue to be read. He describes it as a children's classic that will adorn book shelves for generations to come.
"Grandparents buy this book for their grandchildren," said Myrddin ap Dafydd, director of publishers Gwasg Carreg Gwalch.
"After the Victorian times, it was probably one of the first children's books in Welsh, with naughty characters delightful to children."
Llyfr Mawr y Plant was first published in the 1920s. Its writers, JO Williams and Jennie Thomas, published two further editions before it eventually went out of print.
The books were richly illustrated, with stories for older and younger readers featuring farmyard fowls such as Ifan Twrci Tenau. One of the most popular characters - Wil Cwac Cwac, the duckling - even featured in a cartoon on Welsh language television.
The stage show, adapted by television writer Gareth F Williams, seeks to revive the stories for a new generation of children more used to TV and other forms of media.
It is already proving popular with school groups from Newport to Rhondda Cynon Taf, and teachers have begun using the book in class in readiness for theatre visits.
TES Cymru has four tickets to give away for the November 4 performance of the musical at the Wales Millennium Centre in Cardiff. The first reader to email firstname.lastname@example.org with contact details claims them.