Christian ethics
Free to read here, from Project Gutenberg.
Moral theology
Religio Medici, Hydriotaphia, and the Letter to a Friend
Confessio Amantis; Or, Tales of the Seven Deadly Sins
Life and Death of Mr. Badman
The Social Principles of Jesus
Christianity and Ethics: A Handbook of Christian Ethics
Theoretical Ethics
The Inside of the Cup — Complete
Four Phases of Morals: Socrates, Aristotle, Christianity, Utilitarianism
Morality Without God
Questionable Amusements and Worthy Substitutes
Explanation of Catholic morals
The Inside of the Cup — Volume 03
The Inside of the Cup — Volume 08
The mirror and the bracelet
Der Teufel und die Hölle
The Inside of the Cup — Volume 07
The Inside of the Cup — Volume 01
The Inside of the Cup — Volume 04
The Inside of the Cup — Volume 02
The Inside of the Cup — Volume 06
The Inside of the Cup — Volume 05