Comedian/satirist Bill Maher's documentary about religious fundamentalism is often hilarious. He makes little effort to be even-handed, although he does speak to an exceptionally jovial Vatican-based priest who comes across as more rational and open-minded than most of the staunch adherents who are interviewed.

Mostly, Maher skewers religious extremists of almost all major faiths.

Maher travels around the world and takes his most incisive aim at the use of religion as a rationale for prejudice, discrimination or a call to arms. His wit is razor-sharp, and director Larry Charles (Borat) wisely uses judicious editing to temper Maher's tendency to be snide or arrogant. 

Unlike his HBO talk show, which can tend toward the heated rant, Maher's delivery here is more subtle and his comic timing impeccable. By choosing some of the targets that he does, he often doesn't need to say much. He makes his point by highlighting an Arkansas politician's misuse of a word (in a subtitle) or by letting the camera simply focus on the man's facial expression after he brags that no I.Q. test is needed to run for office. 

Religion's influence on politics, as well as on socio-cultural issues, is Maher's focus. Perhaps he injects his own personal story a bit too much (he refers to himself as "half-Catholic, half-Jewish" in upbringing), though it does add some perspective. He has his smug moments, but so do the believers he interviews.

Maher not only makes a strong case against blind, unquestioning faith, he also brings into sharp relief the more outlandish tenets of many organized religions. He likens the Biblical tale of Jonah and the whale to Jack and the Beanstalk, which will no doubt anger those who adhere to a literal reading of the Bible. 

He points out the similarity between the mythical, the fantastical and the sacred. He questions whether someone who claims to be a prophet or messiah may simply suffer from a delusion or other mental illness. He's a provocateur and as such, his approach is likely to inspire lively debate. 

He's often so comical when highlighting the ridiculous that he draws unexpected laughter from some of the most religious people he interviews.

While most of the movie is entertaining and illuminating, it falters toward the end, when its lighthearted tone grows ominous and preachy. 

In closing, Maher suddenly turns serious and warns viewers to "Grow up or die." Even if you agree with his basic premise, the dire tone feels excessive and melodramatic, and it seems hypocritical to sermonize when targeting religion. 

His point is made most effectively with humor, even if it's caustic and sardonic.