If a book is written about me by an author, do I get royalties?

Nope.  The author is the creative one, and the one who did the work.  You get bupkiss.  

You would have to sue for them. Publishers employ legal teams to see whether their output would leave then open to a claim for invasion of privacy or libel, so the chances of being successful would be negligible (they are also insured against such action). Think how many 'unofficial biographies' are out there and their subjects never see a penny.

no. the person writing it does unless you made some sort of deal with them.

It depends on the law where you live, but in general, you're not entitled to any money unless you sign an agreement to that effect with the author and/or the publisher.

no. Unless you have an arrangement for otherwise (like using a ghostwriter).

No. The author does the work so why would you get money?

Oh, yes. Yes, you do. Unquestionably. US versus Nicholas "Big Nick" Nickleby (1987) and UK versus "The Devil's Ballox" Motorcycle Club (2002) clearly found that if someone writes a book about you you must get royalties to the amount of 87% of all total sales of the book. But don't worry, Si. No-one's ever going to wrote a book about you.

If someone writes a book about you without your permission and you can prove that it's unquestionably about you and that it was done without your explicit consent, then the person responsible for writing it would likely owe you a considerable portion of his or her earnings. Possibly more than that, depending on how strict the laws against libel and defamation are where you live. 

If someone writes a book about you and does so with your blessing, you're not entitled to anything that wasn't agreed on by both parties prior to you authorizing that person to write the book. 

If that sounds both confusing and unfair, remember that what you're asking about is a legal matter, and keep in mind that the law often doesn't make sense and it's rarely fair to everyone. 

If you were to grant me permission to paint a portrait of you and it was agreed that I could do as I wish with the painting and remain free of any obligation to give you anything, if someone were to offer me $100 million for that painting, you'd be SOL, head. And me? I'd be $100 million richer. If you didn't have the good sense and foresight to earn something from the reproduction of your likeness, that would be your problem, not mine. 

Granted, there's only one single painting to flog so there are no royalties involved, but if museums from Sydney to Stockholm wanted to display that painting they wouldn't owe you a sou either. 

The bottom line is that any book that's traditionally published is going to be the product of an agreement between the publisher and the author. If the author's got your consent and everything is on the up and up from a legal standpoint for the publisher to green-light the printing and distribution of that book, you'd be entitled to a whole lot of nothing. 

No.  You won't.  

Nope. Not unless you sign a deal before it’s published