Historical revisionism is the reexamination of accepted history, with an eye towards updating it with newly discovered, more accurate, and/or less biased information.
Broadly, it is the approach that history as it has been traditionally told may not be entirely accurate and should be revised accordingly.
The term historical revisionism is also, however, used to describe propagandists who wish to reexamine history in light of their own ideological position.
The term in this sense is most strongly associated with Holocaust denial.
The term "historical revisionism", or simply "revisionism" is also sometimes used to refer to specific revisionist theories held by the famous chess player Garry Kasparov among others (see [1]), which hold that the events of what are known as the last 3,000 years occurred in either a much shorter or a much longer time frame.
Other revisionist histories, when backed by documented evidence and logical reasoning in peer-reviewed journals, have become the generally accepted history as more information is revealed. For example, German historian Christian Gerlach has interpreted a diary entry by Joseph Goebbels and a newly discovered one from Heinrich Himmler to mean that the date of the decision by Hitler to exterminate the Jews is in December 1941 rather than late spring or early summer as most have till now believed ([1]).
Further, many history books of the past rarely mentioned, if at all, the relationship the European explorers, colonists, and later the United States had with the Native American population (who were referred to as American Indians or Red Indians). In the past, outside of Native American populations, very few would dispute the assertion that Christopher Columbus "discovered" America. Indeed, most of the recent scholarship having to do with Columbus -- and contradicting the image of Columbus as a heroic figure -- can be considered revisionist. (Some, too, is revisionist in the ideological sense of the word.)
Finally, throughout history slaves have not been considered equal to their masters, which has been reflected in the accepted histories of the time.
In the study of the Reconstruction era of the American South, the revisionist interpretation of events has completely replaced the Dunning School interpretation.
During the days of the Soviet Union, dictator Joseph Stalin's regime employed a variety of revisionist tactics to ignore unpleasant events of the past. Soviet school books would constantly be revised to remove photographs and articles that dealt with politicians who had fallen out of favor with the regime. History was frequently re-written, with past events modified so they always portrayed Stalin's government favourably.
There is also a "politically correct" movement in revisionism that can often be found in history materials targeted towards children and young adults.
This type of revisionism effectively seeks to censor some of the less pleasant sides of history, lest it should cause controversy or hurt feelings.
For example, in some American schools the speeches of Martin Luther King Jr are not presented in their entirety, as King frequently used racial terms such as negro, now considered offensive.
Revisionism has also been accused of becoming a "trendy" pursuit, and indeed, bold revisionist theories often get a lot of attention from historians and the media. Some argue that this fosters an attitude of historical apathy, and is encouraging scholars to focus on sensational or obscure parts of history, rather than the well-known and universally accepted.
It has become rare since the 20th century for historical research that sheds new light on past events to cause scholars to revise long-held views, due to the consistently high standard of university-led and independent scholarship.
However, advocates of political causes have consistently sought to promote and defend their views against those of their opponents.
Because of the adoption of this word by holocaust-deniers, the term historical revisionism has virtually become a dirty word, and revisionist a suspect description of a historical work. Holocaust deniers adamantly insist that they are merely correcting a long-established falsehood, and that their publications represent authentic historical research.
Holocaust-deniers have also attached themselves to the issue of the Heimatvertriebenen, and have attempted to use the sympathy for the plight of those Germans who suffered to attempt to put forward their right-wing agenda, often using it to blame the Jews for the suffering of the Heimatvertriebenen, or to retroactively minimise the suffering of the Holocaust.
There is some legitimate opinion that some Zionists have used the Holocaust in an effort to drum up support for their positions and as cover for questionable activities by the state of Israel, see The Holocaust Industry.