Without a doubt, the e-book is practically the biggest thing that’s hit the publishing industry since the invention of movable type. Publishers and e-book resellers are reporting astronomical growth.

At McGraw-Hill, we have been an active player in e-book technology dating back to devices like the RocketBook (one of the first e-book readers) that was launched more than 10 years ago. And today, e-books and e-book distribution is central to our publishing and growth strategy.

From the front lines of the e-book revolution, here are five trends I’m watching.

1. Enhanced E-Books Are Coming and Will Only Get Better

Consumers have already shown that they love e-books for their convenience and accessibility, but ultimately most e-books today are the same as print, just in digital form. The e-book of the not-too-distant future will be much more than text. Interactivity has arrived and will change the nature of the e-book.

Imagine video that shows how to fix a leaky faucet or solve complex math problems in statistics; audio that pronounces foreign language words as you read them, and assessment that lets you check what you remember and comprehend what you just read. These interactive features and more are being developed now and will be on the market in a matter of weeks, not months.

Publishers are already conjuring up designs for the enhanced e-book of the future. Imagine still: If you miss five questions on your geometry test, will your book adapt and change to help you learn the questions and concepts you missed? Will your new novel provide a platform for live exchange with reading groups where you can discuss the book with the author? Today’s enhanced e-books that feature talking heads or out-takes from movies are yesterday’s ideas. Consumers will expect a much greater experience.

2. The Device War Is Nearly Over

Devices are proliferating to the point of confusion. Does a consumer buy a Nook, Kindle, Sony e-reader, an iLex or any one of 20 other dedicated e-readers? Or do they buy an iPad, Galaxy Tab, or other Android tablet? Or do they buy an e-reader at all? Have you ever noticed on a crowded train or bus how many people are reading their phone? And for a growing number of readers, the mobile phone is fine for reading just about anything. But as far as devices go, consumer confusion is likely to drive quick consolidation around a few winners in the market — no one wants to own the next “Betamax for books.”

Because most developers are developing e-reader software that will work on multiple other devices (Kindle also works on the iPad, iPhone, and computers, for example), consumers will care less about the device and more about the user experience of the e-reader software, portability of titles from one device to another, and access to a full catalog of titles.

3. The $9.99 E-Book Won’t Last Forever

Amazon popularized the $9.99 price point for best-seller trade titles, driving the widespread consumer adoption of the Kindle and consumption of e-books. This has caused confusion among many consumers who simply think every e-book should be $9.99 or less. But the majority of titles offered on Amazon are priced above $9.99, especially those with unique interactive features. For professional and technical publishers like McGraw-Hill, our e-books cannot stand the low, mass market pricing some consumers think should be applied to every e-book. Our costs are invested in extensive product and editorial development of sophisticated and technical content; the cost of paper, printing, and binding are a fraction of the real expense. And for some very specific and technical subject areas, our markets are much smaller. We simply couldn’t afford to publish the work if it must be priced at the everyday low, low price of $9.99.

The real opportunity for publishers will be to develop e-books that offer the kind of interactive features mentioned above. Our customers will demand interactive books that provide a much better, more informed and enriching experience. For them, the experience (not the cost) is often the primary driver.

4. The Contextual Upsell Will be a Business Model to Watch

E-books allow publishers to interact with their customers in new ways. Imagine customers who are trying to learn statistics and get stuck on a particular formula. They ask friends but no one can explain it well. They’re stuck.

They click a help button, which points them to the publisher site where they can download relevant tutorials about specific formulas for $2.99. They choose the one they need and get a new learning tool, which helps them progress in their class. Multiply this by hundreds of thousands of students who share similar learning gaps who will purchase through the book (“in-book app purchase”) and it becomes an interesting new marketing opportunity.

5. Publishers Will Be More Important Than Ever

Despite the hype around self-publishing via the web, publishing houses will play an even greater role in an e-book world. Commodity content is everywhere (and largely free), so high-quality vetted, edited content — which takes a staff of experts — will be worth a premium.

At McGraw-Hill, the average technical and reference book engages teams of editors, copy editors, proofreaders and designers to produce a single book. In the digital world, the role of publishers will be larger as new technologies provide for an even greater user and learning experience. Furthermore, with the skyrocketing amount of content being served on the web, customers will seek and pay expert content providers that aggregate and contextualize information for them efficiently and provide highly accurate and specific search options. Publishers with expertise and resources in these and emerging areas will be the ones that write the new rules of e-book publishing.