In my church's calendar, today is St. Athanasius Day. This creed was almost certainly not written by Athanasius (First clue - the Eastern Church seems to not have been aware of it until after 1000 AD. - 2nd clue, it seems to use 5th Century Augustinian Trinitarian concepts and a bit of 5th Century Cyrilic Christological concepts) but was attributed to him because it celebrates the orthodox doctrine of God for which Athanasius was such a witness.
The main text is basically from http://www.bible-researcher.com/ecumenical-creeds.html , which is attributed to Schaaf's work on Creeds.
I have found that because we use it rarely, it keeps a bit of freshness today. The following phrase has particularly stood out for me lately: Unus autem, non conversione divinitatis in carnem: sed assumptione humanitatis in Deum.
I have tagged it with both the Athanasian Creed datatype as well as the BookOfConcord datatype...(Hey - I AM Lutheran)
SDG
Ken McGuire