Every historical narrative is influenced by the point of view of the author, even if the author attempts to remain objective and not let his or her beliefs influence the narrative. Specifically, the author's point of view is manifested in his or her interpretation of events and thematic emphasis. First, authors interpret events differently based on their worldviews. For example, conservative and liberal historians will interpret the same events differently; a liberal might blame unrestrained capitalism for the Great Depression, but a conservative might blame the government policies following the stock market crash for turning a minor recession into a full-blown crisis.
Second, the author's point of view affects his or her thematic emphases. I recall reading several biographies on President Andrew Jackson for a research project during my university years. One biography spent nearly 1/3 of the book discussing Jackson's policies toward Native Americans; another biography devoted just 9 of its nearly 600 pages to this issue. The reason for this disparity is that different authors view certain subjects as more or less important than other authors view the same subjects.