Documentary films relating to matters of religion and belief are always worth knowing about, and often worth checking out.

A new film entitled The Unbelievers, looking at the importance of reason and science — and casting a critical eye upon religious belief — has recently been released.

The film focuses upon noted biologist Richard Dawkins (author of The God Delusion) and physicist Lawrence M. Krauss (author of A Universe From Nothing), following them as they team up for a global lecture tour in which they carry their message and make their case for the importance of both science and skepticism in the contemporary world, and in relation to contemporary issues.

The Unbelievers also features interview segments with a host of like-minded celebrities, including Ricky Gervais, Woody Allen, Stephen Hawking, Bill Maher, Stephen Colbert, Eddie Izzard, Adam Savage, Ayaan Hirsi-Ali, Penn Jillette, Sam Harris, Daniel Dennett, James Randi, Cormac McCarthy, and Michael Shermer (to name a few).

The film’s world premiere, in April at Toronto’s Canadian International Documentary Festival, sold out four screenings — and, according to a Twitter “tweet” from Ricky Gervais, got a standing ovation.

Being a documentary, distribution and screening of The Unbelievers at local cinemas may be limited. Check your local listings, especially of indie movie houses that feature indie films and documentaries. (Or wait for the film to be released on DVD.)

The trailer for The Unbelievers can be viewed at the film’s official website, at www.unbelieversmovie.com.