Inkling

For rewriting the book on e-books.

Inkling publishes beautiful interactive instructional e-books—a huge advancement over the usual flat, boring PDFs under glass and even the flattened text of the ever-popular Kindle. Working with textbook companies has helped Inkling bring the enormous chemistry books of yore to tablets in an easy to digest form that incorporates quizzes and reviews without the hundreds of pages. In February 2013, Inkling upped its game even further: It opened its software to let giant publishers such as Pearson and Elsevier build their own masterpieces, which led to "eight figures" of revenue, says CEO Matt Macinnis. "At long last, we're going to move consumers' concept of the e-book well beyond the crappy text files you download to your Kindle today."

Three of our favorite inkling e-book uses:

1. Master Your DSLR Camera (Open Air Publishing)

Aspiring shutterbugs learn camera settings by dragging a scroll bar under a photo, say, to see how the image quality changes according to shutter speed.

2. Modernist Cuisine at Home (The Cooking Lab)

The cookbook's recipe calculator recalculates the ingredients—and updates a shopping list on your phone!—when you change how many you're cooking for.

3. Gray's Anatomy Review (Elsevier)

Med-school students get interactive quizzes after each chapter so they can track their success.

[Anatomy: Hein Nouwens via Shutterstock]