It’s not a myth.  Two people I know reported this spring that they were offered, and accepted, advances for forthcoming books in excess of $1,000,000.  The authors are serious and knowledgeable people and their books will be informative and will probably sell pretty well.  After their agents take their cuts, they will be able to live comfortably in New York City for several years while planning their next projects.

But will the publishers recover their investment?  [The contributor of this comment will want to skip the rest of this paragraph.]  They will undoubtedly try.  The authors both warned me that accepting a sizable advance entails surrendering control to the publisher of the final product, as well as much of one’s free time.  There will be unwelcome editorial changes as well as a grueling schedule of book tours, often with wine and cheese.   But a quick calculation (not taking into account eventual sales of merchandise, video games, TV contracts, ringtones, and secret revenue streams that the profession has yet to reveal to me) suggests that the publisher will have to count on six figure sales to recover a seven figure advance.  How realistic is that?

Not very, according to Lynn Neary, reporting last September on Weekend Edition:

So what is a good sales figure for any book?

“A sensational sale would be about 25,000 copies,” says literary agent Jane Dystel. “Even 15,000 would be a strong enough sale to get the publisher’s attention for the author for a second book.”

But if that second book doesn’t sell, says Dystel, odds are you won’t get another chance.

By this measure, Eugenia Cheng’s How to Bake π: An Edible Exploration of the Mathematics of Mathematics has been a sensational success, according to a richly illustrated feature article that appeared in the New York Times two weeks ago.   The Times reports that Cheng’s book has sold just about 25000 copies in the US alone, not counting translations.   As for other aspiring writers, Neary’s news is not good.

Just over 1,400 full- and part-time writers took part in the [2015 Authors Guild survey], the Guild’s first since 2009. There has been a 30 percent decline in author income since then and more than half of the respondents earned less than $11,670 (the 2014 federal poverty level) from their writing related income.

“No one likes to see the word ‘poverty level’ on a survey that has anything to do with people you know,” says Roxana Robinson, president of the Authors Guild. “You used to be able to make an absolutely living wage as a writer. You wrote essays and you published them in journals. You wrote magazine pieces and you got paid very well for those. And you wrote books and you got good advances. So being a writer, it didn’t usually mean you would be rich, but it had meant in the past that you could support yourself.”

What happened?

The Authors Guild blames the decline in writers’ income on a combination of factors: online piracy of digital material, consolidation within the publishing industry which has led to more focus on the bottom line, the dominance of Amazon and the rise of self-publishing which has cut into the market for traditional publishers.

The Times portrait of Cheng was charming but mathematically slight.  Steve Strogatz had a cameo, which is not so surprising, since he’s well-known to Times readers for his Joy of X columns, and maybe also because he has managed the exceedingly rare feat of writing successful popular books about mathematics with real content.  More unexpected is a quote from John Baez that gives the reader only the slightest hint of his legendary exuberance:

“Eugenia has gone all the way in,” he said. “She’s trying to explain math to everybody, with or without pre-existing expertise, and I think she’s doing wonderfully.”

The Times author, it’s safe to say, did not go “all the way in.”  There is Cheng’s helpful illustration of associativity with a custard recipe.

You must first combine the sugar and egg yolks and whisk them into a froth before you pour in the cream.

Blend the ingredients in a different order, [Cheng] said, “and you end up with a runny mess.”

To illustrate mathematics, on the other hand, the Times author chose a problem from elementary algebra; hardly the Baez-Dolan Cobordism Hypothesis.

Now for the question on all your lips:  how is MWA doing, on literary agent Jane Dystel’s scale?  Well, it has a long way to go before anyone will call its sales “sensational,” and it may never get there.  But the book is in its second printing, Princeton University Press has more than recovered its (modest!) advance, and discussions of motion picture rights — as it says in my contract

(b) For the licensing of dramatization, public reading, radio, video, sound recording, and motion picture rights, you will receive 75% of the net amounts received by the Press. —

have yet to begin.