What is an angel?

Are angels myth-products of the primitive mind, to be classed with genii, demons and spirits of the earth and air, or do they possess a true spiritual reality? The author explains the Church's teaching on the existence of angels. He then shows the evidence for the teaching as it occurs throughout Biblical history, leading the reader through the labyrinth of historical evidence and separating divine revelations from imaginary myth. Starting with a conviction that angels exist, that they represent grades of perfection, and that they perform some intermediary functions, the author works from these premises to an analysis of what the being of pure spirit actually is. He then summarizes the Thomistic tradition on the subject. The author is also concerned with specific aspects of angelology such as the guardian angels, the archangels, the fallen angels and the angels as messengers.