When writing your book, you may wonder if what you're writing about someone may put you in hot water legally. Each state has its own privacy laws; however, there are a four types of privacy violations that are generally applicable:
1) Publishing private facts that are not newsworthy
2) Portraying someone in a false light
3) Intrusion on seclusion
4) Right of publicity
Let's go over the latter two first.
Intrusion is what you may think of when you hear the word "privacy." A good example of that is someone taking a picture of you inside your home, which you did not authorize.
Right of Publicity
Right of publicity violations occur when you use someone's name, image, and/or likeness for commercial purposes without their permission. Some states only state that the right of publicity is good for one's lifetime; however, some states like California and New York, among others, say that the right of publicity is descendible and can be exercised by someone's heirs. An example in book publishing may be claiming an individual endorsed your book when that is not the case. Another example is using a person's image on your book cover when you have not received permission, which may falsely give the impression that the individual endorses your book.
For a false light claim, an individual has to prove that there has been a publication (widely) that identifies a plaintiff and places the plaintiff in a false light that would be highly offensive to a reasonable person, and the defendant was at fault in publishing the information. The important thing that you need to concern yourself with is whether your statement(s) amount to something that is more than just insulting. The statement(s) has to be "highly offensive."
It is noteworthy that false light does have some overlap with defamation. The main difference is that defamation deals with someone's reputation, while right of privacy concerns itself with offense or embarrassment due to a published statement.
Publishing Private Facts
This refers to publicly disclosing private facts that are highly offensive to a reasonable person that are not a matter of public concern (i.e., not newsworthy). The big concern here is whether what you've written about someone is of public concern. Think of it this way. If someone wrote something about your life that is private that you had no desire to make public, that would be highly offensive to you, wouldn't you be upset if you suddenly found it published in a book for all to see?
So what can you do? Among other things:
1. You can attempt to get consent from individuals who you mention in your book.
2. Corroborate your information, ideally in writing.
3. You can write your book in such a way where it makes it difficult for individuals to determine it is them you are writing about (i.e., creating composite characters).
4. Writing disclaimers.
Everything is a risk assessment, and you need to determine if you're practically able to get permission or if someone may in fact sue you.
If you need an attorney to review your manuscript, please don't hesitate to contact me at firstname.lastname@example.org or 914-775-8774.