★★★ out of four stars Unrated by the MPAA.

Theater: Oak Street Cinema, 7 p.m. today-Tue.

A couple of years ago, Julia Sweeney opened her door to a pair of Mormon missionaries who asked her about her relationship to God. That got her thinking, and reading, and researching, and in time Sweeney was looking at all sorts of supernatural belief systems with profound skepticism. She shaped her spiritual knowledge journey into a one-woman stage show that charted her eventual embrace of atheism. The filmed version of "Letting Go of God" is a no-frills affair, but Sweeney's talking-head presentation compensates for static visuals with soul-searching substance. Sweeney is known as a comedian from her years on "Saturday Night Live," but her show is touching, thoughtful, heartfelt and unfailingly honest.

Sweeney recounts her de-conversion from Catholicism to the belief that the universe is a crapshoot of mammoth proportions. The disillusioning experience behind her change of heart was actually studying the Bible. Her close reading of the text revealed internal inconsistencies, a deity that demanded human sacrifice and who condemned the victimized animal to death "if a man lie with a beast."

Her disbelief expanded wherever she looked. A vacation in Asia brought her face to face with Buddhism's unsavory tendency to blame human birth defects on bad behavior in prior lifetimes. She debunks Deepak Chopra's claims about the occult influences of quantum mechanics, examines the wishful thinking that underlies Deist nature worship, and eventually finds peace of mind in viewing the universe as an awe-inspiring game of chance.

While Sweeney confesses that she misses the sense of divine purpose and love she experienced in church, "the invisible and the nonexistent often look very much alike." Sweeney's quest put her at odds with her devout parents, but their relationship emerged all the stronger for having been tested. You may argue with Sweeney's conclusions, but you must admire her determination to question received wisdom and think for herself.

★★ out of four stars

Theater: Oak Street Cinema, 9:15 p.m. today-Tue., plus 5 p.m. Sat.-Sun.

As former priest James Carroll reminds us in "Constantine's Sword," at various times throughout history both Christianity and Islam have been spread by force of arms. Carroll traces the links between militarism and Christianity, beginning at the Air Force Academy in Colorado Springs, Colo., the scene of quasi-official evangelical proselytizing.

Side trips to Italy, Poland and Germany draw a timeline of church history from the murderous Constantine, founder of the Holy Roman Empire, through the Crusades and the Holocaust. Carroll introduces us to religious leaders who appear to believe that violence is a good thing in the right hands, and others, like a former Academy chaplain labeled a "traitor" for challenging the rise of religious favoritism on the campus.

Carroll covers so much ground, geographically and historically, that the film loses focus. There are compelling stories in this handsomely produced project: the experiences of Jewish Air Force cadets who were harassed, or the double helix of faith and militarism, or the history of Christian religious intolerance, or Carroll's own biography as he journeyed from the priesthood to writing critically about the church. If only he had chosen one topic rather than scattered his efforts among all of them.