I think, for me at least, one of the hardest tasks I have as a nonfiction writer is 1) doing good research, and 2) getting permissions to use quotations and excerpts in my books.
#1 is easier than the second. Facts are facts, and they ARE NOT COPYRIGHTED. Nor can they be under copyright law. Of course when stating facts, how you state them is all important, for if you plagiarize copy and long phrases and excerpts with a fact or two thrown in, well, that doesn't count. Rephrasing and restating is always safer.
#2 is much harder. There are no industry standards in the published world for how you can obtain permission to use a quotation or excerpt from a news article, magazine or book. None.
It's up to the publisher and author to make that process either extremely easy or extremely hard. Mostly it's extremely hard finding access to them in the first place. Some big publishers have permission departments that work well, again, if you can find out how to contact them. I went thru Simon & Schuster for permission to copy and publish 3,000 words from Stephen King's book On Writing. They had a contract and a fee. The contract was good, the fee of $6.00 per copy for the 30 copies of the 14-pages of excerpts I distributed to my writing classes was not that great for my pocketbook, but it was something I wanted to do.
And it would seem actual permission departments are few. So it's a catch as one can proposition getting permission.
That brings me full circle to knowing copyright expirations so that you can cite quotations easily and even recklessly.
Here's the skinny: It's complicated.
1. For most works it's the term of the author's life plus 70 years. So Dickens and Shakespeare are safe to quote. However, the source you use to quote from is probably copyrighted, and your Bibliography should show that.
2. the exception is that any works published after January 1, 1978 when copyright laws changed, is that any such work created after 2002 will not expire until 2047. You and I will be dead by then, so use of any of that material freely is out of the question. One must ask for permission to use anything. Note: Song lyrics are jealously guarded by that industry, so don't even go there unless you want to be sued or go to court.
3. Works that were created before 1978 and published with a proper copyright notice before 1923 are now in the public domain. That's what you can site freely from, works in the "public domain." BUT BUT BUT you must check to see if the copyright was renewed before just using it in your book. Go to www.copyrigght.gov/records/index.html to check.
Bottom line: Go to Lolly Gasaway's rules summary at www.unc.edu/~uncling/public-d.htm to double-check what I've told you here.
Believe, me, neither you nor I have the time, money or patience to be hit with a suit of any kind over the use of someone else's words or writing.
Spend the time necessary and do your research. Great writing stems from great research under all conditions.
If you've had any horror stories, please share them in the Comments below. I'd be interested to know how it worked out.