It's always important to keep our eyes open for "spin" when we talk about history. People tell historical narratives with a spin, with a slant or bias designed to advance their agendas and promote their viewpoints. But sometimes it's not so obvious. Let's take an example from the seemingly innocent topic of the history of American coins.
If we consider the four most commonly used coins (quarter, dime, nickel, cent), and we look at whose picture shows up on them over the years, we might see a trend: in 1950 all four contained the portraits of men. In 1960 and 1970, all four carried the images of men. By 1980, we see the introduction of a new coin: the one dollar coin carrying the image of Susan B. Anthony. By the year 2000, we find a coin bearing the image of Sacajawea, who is not only a woman, but a Native American as well! This narrative shows progress - we've gone from all men, to including women and Indians.
The above paragraph is a narrative, carefully designed to make the "old days" look narrow-minded and bigoted, and present the current time segment as more progressive. The problem is, it's not true. But most readers don't know that, and don't detect the "spin" or bias woven into the narrative.
A more complete version of the story would tell you that only women were pictured on commonly used coins until 1909: Abraham Lincoln was the first male portrayed on a coin when the penny began carrying his image in that year. Not only did coins carry the images of women, but many of them were Native Americans.
Adding those missing facts makes the story look quite different. Now, most people don't really care a whole lot about whose picture is on a coin, but this example of how the story is told is a good example of why we need to be skeptical of anybody's version of history.