Summa Theologica - Part I Q58-62: Of the Mode of the Angelic Knowledge - Of the Perfection of the Angels in the Order of Grace and of Glory

The Summa Theologica (or the Summa Theologiae or simply the Summa, written 1265–1274) is the most famous work of Thomas Aquinas although it was never finished. It was intended as a manual for beginners as a compilation of all of the main theological teachings of that time. It summarizes the reasonings for almost all points of Christian theology in the West, which, before the Protestant Reformation, subsisted solely in the Roman Catholic Church. The Summa's topics follow a cycle: the existence of God, God's creation, Man, Man's purpose, Christ, the Sacraments, and back to God. (Summary adapted from the Wikipedia)

 58. Of the Mode of the Angelic Knowledge

 59. The Will of the Angels

 60. Of the Love or Dilection of the Angels

 61. Of the Production of the Angels in the Order of Natural Being

 62. Of the Perfection of the Angels in the Order of Grace and of Glory