Dear Rhiannon, ( and I think I am also answering Dear Outriders post )
I think I can bypass Armstrong's strong credentials as she is without a doubt the most well informed and unbiased writer on religion of this century.
Her writings on the subject of Mythos and logos, her studies regarding mythos, it goes much deeper than the description of fairytale, in fact if I have understood properly mythos was as valuable a way of thinking as logos ( logical thinking ).
(please remember that this is my way of explaining, I am not a well educated man, handsome and wind swept, just not educated ).
A typical example would be The Book of Job, a terrific myth that not only tells you of a mans trials and tribulations but that this story is timeless, it happens again and again.
And please Outrider I might be thick but even I know we can disregard God and the Devil playing games with Job.
These Myths had a purpose, to take you out of yourself, to teach, to inform, to make you actually think about life and what it was all about.
Oh and in case ippy is lurking, all myths not just Biblical.
Armstrong also states that over time the term myth has been modernised, into what Outrider now classes as a fairytale, but through intensive research of greats such as Socrates, Plato, Buddha, Confucius, she has shown that myth thinking was invaluable.
Logos was 2+2=, Mythos was how we lead our lives, how we treat our fellowman.
Hope the above helps, but maybe there is on the forum someone more scholarly than me who can explain better.
Not fairytales Outrider but there may have been some pointy hats.
Gonnagle.