Catholic Encyclopedia: Aaron
Commentary on the Biblical priest from the traditional Catholic perspective.
http://www.newadvent.org/cathen/01003a.htm

Comparative Index to Islam: Aaron (Harun)
Highlights differences between Islamic and Christian beliefs about the Biblical priest.
http://answering-islam.org/Index/A/aaron.html

Tsaddikim: Aharon HaKohen
Presenting the Chassidic position on the first high priest of the Israelites, including beliefs about his later reincarnations.
http://judaicaplus.com/tzadikim/aharon.htm

Aharon's Forgiveness
Rabbinic commentary on the nature of the high priest's sin regarding the golden calf.
http://www.torah.org/learning/rabbis-notebook/5760/shemini.html

Jewish Encyclopedia: Aaron
Overview of the Biblical priest from the traditional Jewish perspective, including apocrypha and Talmudic commentary.
http://www.jewishencyclopedia.com/view.jsp?artid=4&letter=A

Aaron's Rod
Summary of Jewish, Christian, and Muslim beliefs about the miraculous staff of the Biblical priest.
http://www.jewishencyclopedia.com/view.jsp?artid=5&letter=A

Aaron Seizes the Angel of Death
Commentary of the acclaimed rabbi Rashi on the high priest's encounter with an angel.
http://www.mesora.org/korach-aaron-angel.html

The Golden Calf
Rabbinic discourse on Aaron's complicity in the idolatrous worship en route to the Promised Land.
http://www.mesora.org/goldencalf.html

Bible Prophecy: Aaron
Profile of the priest from a joint Lutheran and Catholic bible study project.
http://www.aboutbibleprophecy.com/p1.htm

Of The Priesthood Of Aaron
Chapter by the first-century Jewish historian Josephus.
http://www.interhack.net/projects/library/antiquities-jews/b3c8.html

Jewish Virtual Library: Aaron
Overview of the Biblical priest's life and leadership.
http://www.jewishvirtuallibrary.org/jsource/biography/Aaron.html

Aaron
Summary and analysis of the high priest's life from a nineteenth-century Christian source.
http://en.wikipedia.org/wiki/Aaron