The Human Body iPad app, developed in collaboration between DK and AKQA, uses interactivity to reveal the structures that make up the human form. We interview Justin Moodie, digital publishing director at DK; and Dan Rosen, head of mobile at AKQA.

DA: For the UI, how did you allow navigation for both readers looking to explore and for specific information?

JM: "We designed two navigation systems: one for the casual browser and the other for the student. The goal for the browsing experience was to be as visual, rich and entertaining as possible while still allowing you to find the content. Examples of this are the carousel off the System pages, the System menu bodies on the bottom left of the screen and the left/right swiping action on the pages. They are beautiful, fun and easy to use ways to see what the app has to offer.

"The second system was designed to be as efficient as possible. We understand that some users will want to access the information but don’t want to take the scenic route. All pages within the app -- expect home for obvious reasons -- have a drop-down menu at the top, which allows the user to go straight from the System level to either Chapter or Story with a couple of taps. We’ve also added free text search so you can see anywhere a term is mentioned. These two combine to allow anyone to get straight to the information they need with very few delays."

DA: While the visual style very much follows from the book, what changes were necessary due to this being viewed on an iPad?

JM: "The Human Body app was designed from the ground up as an iPad app and has only a respectful nod to the book. The organic feel of the app was created specifically for the digital product as were the menus, controls and interface. We did this specifically so that we could take the most advantage of the space available to us and not have to make compromises on the design. At every stage of the design process we pushed ourselves to make the app as ‘DK’ as possible."

DR: "The challenge was taking an oversized A3 book that contained 100s of pages with 1000s of pieces of beautifully crafted complex information and create a simple and intuitive way for users to navigate and understand the complex hierarchy of content.
"When creating the app we had to bear in mind the small screen format and optimise the detailed illustrations so you can zoom in to see the most highly detailed illustrations consistent with the book. Our resulting iPad app enables the viewer to zoom in and around content, such as annotations, illustrations and 3D imagery allowing the display of greater depth, detail and resolution compared to the printed experience."

DA: Give us some specific examples of where interactivity adds a layer of understanding not possible in a printed book.

DR: "Navigation: We had to balance any navigation decisions against our three core reader groups: family, students and the medical community.  The first clear enhancement was losing the contents page.  The App allows readers to go directly to content either through keyword search or via dropdown menu.

"We knew that one element readers loved about the printed book was being able to go to a topic at random by flicking through pages and discovering content.  We enhanced this serendipitous and playful reading experience within the App with the carousel navigation.  As well as providing a useful navigation tool, it allows readers to playfully spin the chapters and stories around to discover new content.
"Content manipulation: Our readers, students and families in particular, wanted to be able to test themselves and each other on identifying parts of the body.  For this we introduced annotation on/off functionality within the app.  Equally younger readers found it difficult to understand how the body systems were layered. [For example], in a focus group, a seven-year-old girl asked ‘Daddy, what’s under my skin? Is it my bone?  The 3D Integrated Body section on the app allows readers to be able to search through body systems in layers.
"Audio/haptic feedback and video: We wanted to take the book and bring it to life in app form as a more sensory experience, introduced where it was helpful rather than for the sake of it.  Focus was on sound design around subtle interface effects to assist readers as they swipe or tap their way around the App.  In order to complete ‘touch’ properly, we introduced haptic feedback on stories of interest so that readers could actually feel the heartbeat, the nerve impulses race and the lungs inflate."

DA: How do you balance the desire to inform with the need to entertain with a book like this?

JM: "The iPad allowed for so much interaction that we had to remind ourselves to focus on the content. Sometimes this was agonising, particularly when we had to decide between an amazing feature and having all the content we wanted. I think we struck a good balance -- the app has content and authority to make it suitable for students but is easy enough to use, with enough hidden gems, that everyone will enjoy it."