Resources for Ethical Theories

1. Consequentialism — William H. Shaw

2. Deontology — David McNaughton and Piers Rawling

3. Rights — George W. Rainbolt

4. Virtue Theory — Rosalind Hursthouse

5. Epistemic Vices, Virtues, and Ethical Reasoning — Quassim Cassam

6. Pragmatic Ethics — Hugh LaFollette

Aristotle

Nichomachean Ethics — The main statement of his ethical theory.

Marcus Aurelius

The Meditations — A classic statement of Stoic thought, from the Roman Emperor, Marcus Aurelius.

Epictetus

The Enchiridion — Another short statement of Stoicism, written by a Roman slave.

David Hume

Treatise of Human Nature, Book III ("Of Morals") — Philosopher Annette Baier argues that feminist ethical theory is indebted to Hume's moral theory.

Immanuel Kant

Groundwork for the Metaphysics of Morals — The main work where Kant develops his moral theory.

William James

"The Moral Philosopher and the Moral Life" — Lecture to the Yale Philosophical Club. The lecture was published (1891) in the International Journal of Ethics.

John Dewey

Human Nature and Conduct — The development of Dewey's ethics.
How We Think — Although not expressly a book on ethics, his account of thought both shapes and reflects his views on ethical thought.

John Stuart Mill

On Liberty — The classic defense of freedom of speech and action.
Utilitarianism — The statement of his general ethical theory.
Utilitarianism (Abridged) — A heavily abridged version of the book.

Adam Smith

The Theory of the Moral Sentiments — Smith was influenced by, but ultimately rejected, Francis Hutchison's "moral sense" theory.

Commentaries on Theories:

Ted Honderich — Consequentialism, Moralities of Concern, and Selfishness
Geoffrey Sayre-McCord — Lectures on sections I and II of Kant's Grounding for the Metaphysics of Morals

Other Theoretical Issues

Lester Hunt — Flourishing Egoism from Social Philosophy and Policy (1999), a defense of a particular sort of ethical egoism.
Hugh LaFollette — The Truth in Ethical Relativism [pdf] from Journal of Social Philosophy, 1991, 146-54 and The Truth in Psychological Egoism from Reason and Responsibility (7th edition).
James Rachels — His Wikipedia Page contains links to many of his most important works on ethics.

Links to multiple sites on ethics:

Philosophy Papers — An amazing resource! Search an enormous database of philosophy articles. Read articles posted on the web or available (electronically) through your university library (you will have to configure your proxy server for off-campus library access; instructions are on the site and easy to follow).