Most western criticism of religion focuses on the Abrahamic religions—particularly Christianity, Judaism, and Islam — with titles such as Why I am not a Christian, The God Delusion and The End of Faith representing some popular published books. Not all the criticisms would apply to all religions: criticism regarding the existence of god(s), for example, has very little relevance to some forms of Buddhism.

Critics consider all religious faith essentially irrational.

Many critics claim dogmatic religions are typically morally deficient, elevating to moral status ancient, arbitrary, and ill-informed rules that may have been designed for reasons of hygiene, politics, or other reasons in a bygone era.