Nora Roberts took the top spot on the Mass Market Paperback Bestseller list in the December 10, 2007 Publishers Weekly with her novel Blood Brothers, which was to be expected. But what I didn’t expect to see was a brief sidebar that said “Roberts is the most prolific writer ever.”

That couldn’t be, could it? I knew that Roberts had probably written 200-250 novels, which might make her the most prolific author of the past 20 years, and if the claim has been qualified in that way, I’d have had no problem with it. But the most prolific writer ever? Wouldn’t that be Georges Simenon, who wrote more than 500 books?

A search of the Web turns up this list, originally published in one of the People’s Almanac volumes between 1975 and 1981. Georges Simenon is indeed there, but even his astonishing output, shown as 500+, turns out not to get him a rank higher than #9. The most prolific author, according to this list? Mary Faulkner, who wrote 904 novels under six pen names, including Kathleen Lindsay. Did Nora Roberts really break this record?

Her own site doesn’t answer the question. We’re told that “She’s had 147 New York Times bestsellers including 18 written as J.D. Robb and one written together with J.D. Robb,” but I can’t find the number of total books there. This list credits Roberts with 197 novels. I don’t mean to denigrate her accomplishments, since that certainly is an impressive number, but it isn’t even enough to put her in the top 20, since L. T. Meade needed 258 books books to her name to occupy that spot.

Anyone out there have an idea on what basis Publishers Weekly made this claim, and who’s truly the most prolific of them all?