The media blog at the Web site of the United States Conference of Catholic bishops has a “Social Encyclical Primer” that sets out the history of papal encyclicals on social justice themes.

Read commentary at InsideCatholic by Deal Hudson from July 20, 2009, who has consulted on Catholic issues for Republican officials.

Read a July 7, 2009, analysis by the Rev. Thomas Reese, posted at The Washington Post site. Reese is a leading commentator on church issues.

Read a July 7, 2009, analysis by John L. Allen Jr. of National Catholic Reporter.

Read a July 7, 2009, analysis by the Rev. Drew Christiansen, editor of the Jesuit weekly America and a leading Catholic social ethicist.

Read the official Vatican text of the encyclical in English.

Peter Laarman of Los Angeles is executive director of Progressive Christians Uniting and an ordained United Church of Christ minister. He is editor of the just-published Getting on Message: Challenging the Christian Right from the Heart of the Gospel (Beacon Press, 2006) and knows a lot of other groups active on this subject.

Greg Boyd is senior pastor of Woodland Hills Church in St. Paul, Minn., and author of The Myth of a Christian Nation: How the Quest for Political Power is Destroying the Church, in which he says American Christians should seek to build the kingdom of God instead of building political power.

Jan G. Linn is author of Big Christianity: What’s Right with the Religious Left (Westminster John Knox, 2006) and a co-pastor of Spirit of Joy Christian Church (Disciples of Christ) in Minneapolis. A former college and seminary professor, Linn calls himself a “recovering fundamentalist” who wants to reclaim the idea of Christianity as generous, or liberal, and tolerant.