Visitors ask...Angels, Archangels or Guardian Angels
New Advent is a remarkable website for checking Catholic news, for finding a great Catholic Encyclopedia, for searching the Summa of Saint Thomas Aquinas, for looking into the Church Fathers, for checking the Bible and so on. So, here is what the New Advent Encyclopedia has to say on Angels, on Guardian Angels, on the Early Christian Representation of Angels, and on the Feast of the Guardian Angels.
Hope this helps! It is a great place to start. And, look into the book by Peter Kreeft!