Lady Charlotte Guest's translation of The Mabinogion tales in the 19th Century is now available as an application for the iPhone.
Revel Guest said the new "app" could bring her great grandmother's work to younger people.
Many of the tales are thought to be up to 1,000 years old.
Ms Guest, who lives in Powys, said: "The more people who can have the pleasure of reading those lovely, lovely stories, the better.
"I think it will bring her work to a younger audience which is great. They are stories which very young people can enjoy."
The tales came to general prominence following Lady Charlotte's translation in the mid 19th Century under the title The Mabinogion.
The stories themselves are much older and are from an oral tradition of storytelling featuring supernatural elements.
Ms Guest, chair of the Hay Literary Festival and an author, film-maker and former BBC journalist, believes the stories themselves are important rather than how they are read.
"I don't think it [electronic devices] will stop people buying books because I think there's something about buying books that's unique," she said.
"The more people who can have the pleasure of reading those lovely, lovely stories [the better]. I think it's great.
"I think that's where it's all going anyway."
Hay Festival director Peter Florence said he likes the idea of books such as The Mabinogion being available electronically.
"I think it's fantastic. These books are out of copyright and should be in the public domain," he said.
"It should be every child's right everywhere to have these stories as part of their heritage. It's absolutely thrilling."
The Mabinogion mobile phone application is available to download for free.
The Apple website says: "The Mabinogion is one of the masterpieces of world literature, and a must-read for anyone who wants to have an understanding of Celtic lore."
A descendant of the woman who first translated a group of medieval Welsh folk tales hopes technology will bring the stories to a whole new audience.