There are three ways to properly use another author's words or ideas:
Quote
Use quotes when you wish to retain the exact wording of the author. Quotes should be used sparingly, and shouldn't come from only one information source. Quotes are best used:
Quotes must be word for word, enclosed in between " ", and must be credited to the original author.
Paraphrase
Paraphrasing involves taking the source material and putting it into your own words. The paraphrased portion should be about the same length as the original, and should maintain the original source's meaning, as well as all of the details. Be careful when paraphrasing--changing just a few words or changing the sentence structure slightly is not paraphrasing, it is plagiarizing.
Good paraphrasers will read the source material, pull out the main points, and using their own words (without adding personal opinions or ideas) convey these main points to the reader. Paraphrased information must also include an attribution to the source of your information. Paraphrasing is best used:
Summarize
Summarizing condenses the original piece of information, in your own words. When should you summarize? Summarize the information you're using when details are less important, and when you want to present an overview of the information. Good summarizers will read the text, pull out the most important pieces of information, and using their own words, will present these pieces of information to the reader. Summarizing is best used: