Dubious historical resources

The following is a canon of historical resources (often cited as though they were completely historically accurate) which may well be open to a considerable degree of question and must be used with the greatest of care:

The Anglo-Saxon Chronicle
The Calendar of Saints (in any edition)
Herodotus
Histoire de l'Inquisition en France has also been shown to be a deliberate fabrication.
The Historia Regum Britanniae History of the Kings of Britain by Geoffrey of Monmouth
The Hitler Diaries, which were a complete forgery.
The Liber Pontificalis
Plutarch, and other authors whose stated aim is to write exemplary biography
Religious texts (Bible, Quran etc.), intended to support a particular doctrine.
The Scriptores Historiae Augustae, which some historiographers think was intended as a joke.

The following could be included on the list, but is rather more of a humorous book than a historical resource, containing deliberately mangled history.

1066 and All That: A Memorable History of England

Also in citing historical resources keep in mind that what may generally regarded as truth by one generation of historians, may become extremely controversial by the next generation, who may not only have more complete facts, but may also be looking at the situation with a different set of historical biases. Case in point, lots of things that have been written about the History of China, in particular the post-Song "decline", anything about Zheng He, the 1911 revolution, the interaction between China and Europe in the 19th century, the interaction between China and Europe before the 19th century.

See historical revisionism for more discussion of the revision of historical opinion.