The ongoing conversations about the growth of e-books focus on how fast the market is transforming, whether e-book sales are cannibalizing print book sales or expanding readership, and what the potential ramifications and implications of these changes are.

I hear people say things like, “Yes, e-books are only a small percentage of total book sales now, but you can see how they’re going to be 60 percent or 70 percent of the market in a few years.” And I say to myself, Really?

After all, the “book industry” is not just one industry; books are purchased by different types of users and for different reasons. So it stands to reason that different parts of the market will transform at different speeds.

When you break out data from Bookscan for broad categories of physical books sold in the first quarter of 2011, here’s what you see:

So the single largest category of physical books sold, according to Bookscan, is adult nonfiction.

Again via Bookscan, these were the five largest categories of adult nonfiction for Q1 2011:

But what’s selling in e-book formats is primarily narrative. The only solid data I can cite are our own figures and the e-book bestsellers lists from individual e-tailers, which are dominated by fiction.

For example:

Among the BN Nookbook top 100 bestsellers, there were 12 nonfiction e-books.

On the list of Kindle top 100 bestsellers (paid), there were 16 nonfiction titles.

These counts were taken at one point a few weeks ago, and these lists change hourly, but when I checked back three other times, the results were roughly the same—less than 20 percent of the bestselling titles were nonfiction.

This is pretty much in line with what publishers are generally reporting and with what we see at Sourcebooks.

As the charts below show, most sales of our physical books for adults are of nonfiction, and most sales of our e-books for adults are of fiction.

And the same breakout for e-books:

Within nonfiction, we’ve found reference the hardest category to get right in e-books. Our reference books are highly formatted—lots of subsections, sidebars, pictures, diagrams, pullquotes, and so on. They’re “browseable,” “dippable,” not necessarily linear reading experiences. All the things that we put in a printed reference book to make it more experiential are the very things that make it harder to replicate as an experience with an e-book.

The other difficult transformation area right now is children’s books (as distinct from young adult books). E-tailers’ bestseller lists, data reported by publishers, and our own data are not suggesting strong conversion to e-books yet for juvenile books, except for crossover YA titles such as The Hunger Games and Twilight.

Right now, stories seem to be at the heart of e-books. Even the successful nonfiction e-books we’re seeing skew to narrative; they’re memoirs and biography and history—all stories, and all linear reading experiences.

Are apps the future of adult nonfiction and/or children’s books? We’ve been thinking a lot about what digital might look like for illustrated children’s books as well as for reference products. Interestingly, the Books bestsellers list on Apple’s App Store includes a lot of illustrated children’s books, and I suspect we will make progress with apps and Web sites. That’s why we decided to turn the #1 bestselling Fiske Guide to Colleges into the iPad app Fiske Interactive College Guide. And it’s an idea at the heart of the development work that we’re now doing with our authors and other partners.

Dominique Raccah is the CEO and publisher of Sourcebooks, the largest woman-owned trade book publisher in the country, which has now produced 25 New York Times bestsellers and more than 20 national bestsellers, and which got involved early with digital book projects, iPhone and iPad apps, enhanced e-books, and digital partnerships. She currently serves as chair of the Book Industry Study Group.

Upcoming on E-books

Reports from IBPA members on publishing e-books will appear in next month’s Independent. Thanks to everyone who’s already shared the wealth of e-book experience. If you haven’t done that and you’d like to, please e-mail judithappelbaum@aol.com about what titles you’ve issued as e-books, whether they’re related to books in conventional formats, what you’ve done to market them, and what you’ve learned about the kind(s) of subjects, formats, markets, and sales channels that are most likely to lead to e-book success—or failure.