A series of children’s books.
This series is now banned in the wizarding world because they have been found to cause nausea, sometimes to the point of actual vomiting (FW). Some of the Tales were re-workings of original tales by Beedle the Bard designed to fill "the pure minds of our little angels with healthy, happy thoughts, keeping their sweet slumber free of wicked dreams and protecting the precious flower of their innocence." (TBB/WHH).
These Tales would seem to be a reference to Beatrix Potter, whose best-known work is The Tale of Peter Rabbit.