This is a huge collection of fables, tales and short stories that are believed to be written by Aesop, a slave and a gifted storyteller who lived in Greece, BCE. These stories have been translated and popularized by various historical figures and are still being reinterpreted by numerous artists, writers and other folks from the popular/artistic circles.
It's a well of inspiration, so, no wonder so many cultures and nations are praising it and using it as a source of illumination. By the way, tons of Aesop's stories are lost in time, while many others are being wrongly ascribed to him, even though he had nothing to do with them. Numerous proverbs, jokes, aphorisms and short tales were written before or after the man and didn't even come from the Greek culture.
The historians are still including and excluding chapters from it, trying to turn Aesop's Fables into an authentic collection of the man's writings. At the same time, they are adding all kinds of new materials to the book that are written by some modern-day writers. The bottom line is - regardless of the content, Aesop's Fables is much more than just a collection of tales: the author talks about religion and politics in a unique, engaging manner.
Now, despite the fact that Aesop addressed his thoughts and opinions to the adult audience, some of his stories were "reshaped" to fit the kids and were vastly used to educate the youngsters after the Renaissance. The greatest writers in history praised Aesop's Fables and called it one of the most important books to ever be published. So, if you love reading insightful, epic and monumental books, just know that it doesn't get any bigger that Aesop's Fables!