Questions about when to indent paragraphs may constitute typographic minutia, but getting it right is important nonetheless, especially if you intend to produce writing that will be professionally published.
Many people believe that every single paragraph in a piece of text should be indented. This is actually unnecessary. You should use indentation to indicate a new paragraph. Given the fact that it is pretty obvious that the first paragraph is a new paragraph, there is absolutely no need to indent it at all.
Robert Bringhurst, author of The Elements of Typographic Style, describes it as follows:
The function of a paragraph indent is to mark a pause, setting the paragraph apart from what precedes it. If a paragraph is preceded by a title or subhead, the indent is superfluous and can therefore be omitted.
His wise words are backed up by the “fount of all knowledge,” Wikipedia: “Professionally printed material typically does not indent the first paragraph, but indents those that follow.”
Of course, as usual with these things, not everyone is in agreement. There are some style guides that say you should always indent the first paragraph in a written document. Take the Associated Press style guide, for instance. They dictate that all paragraphs should be indented. However, do bear in mind that these style guides are intended for newspapers and what is useful for a newspaper may not be appropriate for your written document.
As with many issues of style, it is all about consistency. If you really do insist on indenting the first paragraph, make sure you do so every time.
And one more thing…
Want to make sure your written English is absolutely perfect? Then you have to try Vappingo’s editing services.