All encyclopedic content on Wikipedia must be written from a neutral point of view (NPOV), which means representing fairly, proportionately, and, as far as possible, without editorial bias, all of the significant views that have been published by reliable sources on a topic.
NPOV is a fundamental principle of Wikipedia and of other Wikimedia projects. It is also one of Wikipedia's three core content policies; the other two are "Verifiability" and "No original research". These policies jointly determine the type and quality of material that is acceptable in Wikipedia articles, and, because they work in harmony, they should not be interpreted in isolation from one another. Editors are strongly encouraged to familiarize themselves with all three.
Achieving what the Wikipedia community understands as neutrality means carefully and critically analyzing a variety of reliable sources and then attempting to convey to the reader the information contained in them fairly, proportionately, and as far as possible without editorial bias. Wikipedia aims to describe disputes, but not engage in them. Editors, while naturally having their own points of view, should strive in good faith to provide complete information, and not to promote one particular point of view over another. As such, the neutral point of view does not mean exclusion of certain points of view, but including all verifiable points of view which have sufficient due weight. Observe the following principles to achieve the level of neutrality that is appropriate for an encyclopedia:
Avoid stating opinions as facts. Usually, articles will contain information about the significant opinions that have been expressed about their subjects. However, these opinions should not be stated in Wikipedia's voice. Rather, they should be attributed in the text to particular sources, or where justified, described as widespread views, etc. For example, an article should not state that "genocide is an evil action", but it may state that "genocide has been described by John X as the epitome of human evil."
Avoid stating seriously contested assertions as facts. If different reliable sources make conflicting assertions about a matter, treat these assertions as opinions rather than facts, and do not present them as direct statements.
Avoid stating facts as opinions. Uncontested and uncontroversial factual assertions made by reliable sources should normally be directly stated in Wikipedia's voice. Unless a topic specifically deals with a disagreement over otherwise uncontested information, there is no need for specific attribution for the assertion, although it is helpful to add a reference link to the source in support of verifiability. Further, the passage should not be worded in any way that makes it appear to be contested.
Prefer nonjudgmental language. A neutral point of view neither sympathizes with nor disparages its subject (or what reliable sources say about the subject), although this must sometimes be balanced against clarity. Present opinions and conflicting findings in a disinterested tone. Do not editorialize. When editorial bias towards one particular point of view can be detected the article needs to be fixed.
Indicate the relative prominence of opposing views. Ensure that the reporting of different views on a subject adequately reflects the relative levels of support for those views, and that it does not give a false impression of parity, or give undue weight to a particular view. For example, to state that "According to Simon Wiesenthal, the Holocaust was a program of extermination of the Jewish people in Germany, but David Irving disputes this analysis" would be to give apparent parity between the supermajority view and a tiny minority view by assigning each to a single activist in the field.