Writing an autobiography or memoir comes with a risk of being sued. You write about real people, and if you write something bad about them, they might retaliate with a lawsuit. Just because a book should be protected by freedom of speech does not mean someone won't try to sue. There are few ways a writer can protect himself from a lawsuit while writing the autobiography and afterward.
Write the truth. Telling a small lie can actually harm the writer. When you write a small untruth about someone, she might call you a liar and sue for defamation of character. If the autobiography or memoir is 100 per cent true, there will be less chance of a lawsuit. If someone does try to sue for defamation of character, you have truth on your side, and have a high chance of winning the case.
Change names and places in the autobiography or memoir. Everything that happens in the book should be the truth, except names and places. This protects the people in the book from being recognised by neighbours, acquaintances and co-workers with whom they would not normally share their life information. Do not change the places in the book if they are integral to your life story. This will not provide full protection to the people in the story, but might put their minds at ease a little. If they feel safe, they will be less likely to sue.
Get a lawyer. After the book is finished, show the manuscript to your lawyer. The lawyer can help prepare for any lawsuits and even help prevent them from happening in the first place. The lawyer might be able to tell you if something in the autobiography is particularly dangerous and will likely cause a lawsuit. Even though you are trying not to get sued, being prepared with a lawyer on your side is always a good idea.
Write a release form or have your lawyer write one up for you. Anyone mentioned in the autobiography or memoir must sign one of the release forms. These forms protect you from getting sued. By signing the form, they are giving you permission to use their name, information and life history in the book and they cannot sue you if the book has negative consequences for them. Let them read the manuscript if they ask. You just might get more of their side of the story and can use that in the book. See Resources for a general release form example.
If there is a very high risk of being sued, you can't get release forms signed, or you are writing about touchy subjects surrounding loved ones, you might want to change the autobiography into a novel. This is when you should lie about nearly everything, but keep the important truths in the story. In a novel, the people become characters, and can become unrecognisable as real people in your life. You are still getting your life out there to be heard, but you can't be sued for a "fiction" book.
No matter what you do to avoid being sued for an autobiography or memoir, you still might be sued. Follow the steps and you should come through the lawsuit unscathed.