We can all agree on lots of things when it comes to writing. For example, everyone knows that grammar is important, and that proper spelling makes for good readability. Capitalizing proper nouns and lowercasing most other words make things clear for your readers. And most punctuation is pretty standard. Generally, if you’re sloppy in these areas, people will just put your text down, or worse, throw it away. But there are many things editors and publishers don’t agree on, simply because they’re following different style guides. For example, a psychology researcher will follow a style guide that is very different from the style guide a marketer who is writing web copy for a business will follow. The end result is their published works can look quite different.
Style guides exist to establish a set of standards for the writing and design of written works, either for general use or for a specific publication, organization, or industry. And due to this, they don’t always have the same set of standards, as different style guides exist to address the needs of different sets of readers and writers.