Inserting Editorial Comments into a Quote
At times, you will find it necessary to add an editorial comment within a quotation in order to clarify terms or references which, having been pulled from their original context may not be as clear to your reader as they are to you.
Understanding your audience will help you decide what needs clarification. Bear in mind they may not have the same research and scholarship under their belt as you. The terms and references in a quote may be unfamiliar and need explaining.
Under such circumstances you may either insert an explanation, within brackets (), directly after the word or phrase needing clarification or, you may replace it entirely with the bracketed word or phrase.