She says her word count is up to 5000 a day--"You can't fall behind," she says. She's done books on Michael Jackson as well as the marriage of model Jordan (Katie Price) to cage fighter Alex Reid.
The time from concept to shop can be as little as six weeks.
The leader in this factory farming side of publishing is John Blake, who started this trend in the UK with a rapid-response bio of Heath Ledger when he died. The biggest outlet for these books is the supermarket chains. Sometimes they even come up with an idea and pitch it to the publisher.
The author's fees typically are £3000 to £10,000 and maybe a share of the royalties if a book is a hit--not so bad if you're cranking out 5000 words a day. These are not long books, so that would mean turning out a manuscript in 10 to 12 days. There's a certain amount of research involved, but I suspect it's not deep or extended. Also, the books tend to feature lots of photos, which cuts down on the word count as well.
It's not a side of writing that interests me personally, as a writer or a reader, but it's interesting to find out how it works.
(For help writing your book, see mine: "Your Writing Coach," published by Nicholas Brealey and available from Amazon and other online and offline booksellers.)