Articles that should be easily accessible to a non-academic audience:

An interview published in The Believer in August 2005, about the foundations of morality. [Tamler Sommers was one of the best interviewers I've ever spoken with.]

Haidt, J., & Joseph, C. (2004). Intuitive Ethics: How Innately Prepared Intuitions Generate Culturally Variable Virtues. Daedalus, pp. 55-66, Special issue on human nature.
[Cited in Ch. 9: A general theory of where morality comes from, and why sets of virtues differ across cultures, even though the foundations of morality are universal]

Haidt, J. (2005). “Disgust and Elevation: Opposing Sources of ‘Spiritual Information’”. In C. L. Harper, Jr. (Ed.), "Spiritual information": 100 perspectives. Philadelphia, PA: Templeton Foundation Press.
[A short article written for a volume in honor of Sir John Templeton. It extends the ideas of chapter 9 on divinity.]

Articles that may be a bit more challenging (But hey, no part of psychology is rocket science).

Haidt, J . (2001). The emotional dog and its rational tail: A social intuitionist approach to moral judgment. Psychological Review. 108, 814-834
[Cited in Ch. 1; Argues that moral judgment is mostly a matter of quick gut feelings or intuitions; moral reasoning is usually made up after the fact]

Haidt, J. & Rodin, J.(1999) Control and efficacy as interdisciplinary bridges. Review of General Psychology, 3, 317-337.
[Cited in Ch. 5: A review of when and why a sense of control is good for people]

Haidt, J., Rosenberg, E., & Hom, H. (2003). Differentiating diversities: Moral diversity is not like other kinds.  Journal of Applied Social Psychology, 33, 1-36.
[Cited in Ch. 8; people want demographic diversity, but not moral diversity]

Haidt, J., & Hersh, M. (2001). Sexual morality: The cultures and emotions of conservatives and liberals. Journal of Applied Social Psychology, 31, 191-221.
[Cited in Ch. 9; Conservatives have a broader moral domain, including the ethics of community and divinity. Liberals have a narrower domain, relying mostly just on th ethics of autonomy]

Keltner, D., & Haidt, J. (2003). Approaching awe, a moral, spiritual, and aesthetic emotion. Cognition and Emotion, 17, 297-314.
[Cited in Ch. 9: A review of research on awe across many disciplines]

Rozin, P., Haidt, J., & McCauley, C. R. (2008) . Disgust. In M. Lewis & J. Haviland (Eds.) Handbook of emotions, 3rd Edition, New York: Guilford Press.
[Cited in Ch. 9: A comprehensive review of research on the emotion of disgust]

All of my other research articles can be found on my academic home page.