A tale of the digital ebook in the tablet era

14 minute read

Books used to be simple objects. You pick one, open it, read it. But what is a book today? Or a magazine? We don’t know anymore. Trying to use the standard definitions from The Random House Dictionary, we find these:

  1. a written or printed work of fiction or nonfiction, usually on sheets of paper fastened or bound together within covers
  2. a number of sheets of blank or ruled paper bound together for writing, recording business transactions, etc.
  3. a division of a literary work, especially one of the larger divisions

Not very useful, is it? None of them really apply to the idea of book we have in our head today, with the digital publishing revolution happening.


It’s clear that none of these definitions is meaningful anymore. However if we start digging we see that the definition of book was fuzzy even before. We have photobooks, without a single written word. We have gamebooks and dictionaries, where there’s no linear sequence. We have popup books, where not even the limit of the page exists anymore.

We can however find an interesting perspective if we consider the book in terms of the man-object interaction. There are two elements that interplay in this regard:

  1. We are conditioned by units and portion sizes: by default, we try to finish our food portion (Rolls, Morris, Roe, 2002). If we pick up a book we expect it to be a thing giving us a complete view on the topic. Maybe partial, subjective or a piece of a story, but still self-contained. Any publication sets this kind of expectation, regardless of length or any other factor. If I read a 500 pages book or a 50 pages book on “Introducing the theory of colour”, they are both introductions and I expect them to give me an overview of it, it’s just that in one case it will be more exhaustive than the other.
  2. Our mind tend to see completeness of forms from an incomplete stimuli, also known as the law of closure (Wertheimer, Rock, Palmer, 20th century). A book is a unit of something, we perceive it as a unit of content, because that’s how we perceive the world. This sets a book apart from a lot of different other forms of written content: you can split the content of a book day by day in a newspaper, but it won’t be perceived anymore as a book, even if it was in origin. The perceptive element of a unit thus must be present.

If we combine these two perspectives we can then define a book as:

A cognitive object perceived as a single item that satisfies a promise through the process of reading.

The Content

From the content perspective we have very different approaches. We can summarize them in two high-level interaction modes that condition the attitude we have toward the book and the kind of knowledge it represents.


  1. Sequential mode: it’s a passive approach, where the reader has the “tell me something” attitude and it’s more experiential and educative. It’s the usual book with a story in, or a textbook that leads to a growing set of knowledge building one upon the other.
  2. Associative mode: it’s an active approach, where the reader has the “let me choose” attitude and it’s more inquisitive and creative. It’s the concept of the dictionary, gamebook or reference book, where the sequence is choosen by the reader.

That’s all great, but didn’t we know all of this before? Ebooks existed since a long time ago. That’s true, but there’s a second element. Beyond the idea of a single unit of content, regardless of its structure.

The Object

The book needs the right form of physicality to exist, because the reading activity requires a specific kind of affordance. Science fiction has already shown us excellent examples of what a book could be.


We have the Hitchhiker’s Guide to The Galaxy.

“A screen about three inches by four lit up and characters began to flicker across the surface… Ford pressed a large red button at the bottom of the screen and words become to ondulate across it. At the same time, the book began to speak.”


We have also another excellent example: Star Trek’s PADD.

“Consisting of a large touchscreen display and minimalistic manual interface or control panel (generally only one or two buttons), the typical PADD is used for a variety of functions.”

There it is. Except for the large red button there for comedic purposes, both the descriptions fit today’s tablets. This physicality is the final element that triggered the final lift-off of the ebook concept as a worldwide industry revolution.

The book from an interaction perspective must then be perceived as the combination of a unit of content plus a fitting physical support. Notice that due to digitalization, the physical support isn’t the book itself, but at the same time it’s needed to trigger a set of behaviours that are deeply tied with the reading porcess. You wouldn’t take a 15″ laptop in your bed to read a bit before sleeping, right? Or you wouldn’t slide a 13″ laptop in your small bag to read a bit while you commute. That’s why physicality is critical even in the digital world.

The Design of Digital Books

If you take away the fact that you can have more than one book in a Kindle, you see that the object is exactly a book following the definition I gave above: a cognitive object perceived as a single item that satisfies a promise through the process of reading, where the ‘item’ is a fitting physical object with the right affordances.

The Kindle interaction model is clearly digital but cleverly adapted on the normal way you page through a book.

Habit shapes behaviours, and that’s a key element in designing these new interfaces. Even the book at the beginning might not have been that simple.

Have a look at this video for a comedic take on the subject.

Today we can build on the knowledge of the book-reading behaviour plus the knowledge coming from the digital realm. This means we have two different paradigms that can interplay. We have the book paradigm, where pagination happens horizontally, page by page, and the digital paradigm, where the user on a page can scroll down as long as needed.

The digital book allows for any combination of the two, and it’s not surprising that almost every publication out there implements a model where the user can swipe horizontally to change page or section and scroll vertically to read through it.


Book means turn.

Screen means scroll.

A way to suggest this kind of behaviour is to use closure and animations to hint that. Content cut vertically on the bottom edge of the screen will nudge users to scroll, while a simple horizontal animation can show briefly that there’s something more on the right, suggesting a swipe gesture. All our knowledges from the interaction design for screens can play well in this new generation of books.

Beyond the Book

The digital revolution brought us also a lot of different kinds of content. We have Flipboard, Zite, Pulse, and many others that present content with interactions models that are sometimes incredibly book-like, reproducing even page turns and newspaper typography, but aren’t inherently books. Nobody refers to them in that way.

The reason is simple if we take the interaction perspective as above: yes the object is correct and the model is correct, but the content isn’t a self contained unit. We have thematic streams of small articles, not units of content.

As you can see the definition of book above coming from more a cognitive perspective works well with our expectations.

I want to add that this doesn’t mean that the solutions above don’t work. They work. It’s just that we don’t perceive them as books, they are less exhaustive, less permanent, and they are read in a different way.

ePub’s failure

Epub is failing in this regard for a very simple reason. It is a standard that was defined first as a pure way to deliver “book” content to devices with very little power and not much screen estate. The standard has always been massively skewed on the idea that text and portability is the most important thing.

ePub version 2 states:

“This specification does not mandate specific rendering behavior”

ePub version 3, recently released, states:

“CSS3 properties were selected based on their current level of support in Web browsers, but support for them in Reading Systems and User Agents is not guaranteed”

In version 3 they even go to the extent of saying they were purpusefully doing that in contrast with HTML. And the reason is simple: “EPUB Publications, however, are designed to maximize accessibility for the visually impaired”.

There isn’t much we can do about it. ePub sacrifices everything on the altar of readability. While I agree with the concept, I can’t agree with keeping the standard updated and pushed in a world where we have devices like tablets and e-readers with browsers built in, great screens and lot of power.

Without a powerful and simple standard we are condemned to the whims of companies: iBooks Author is in a way similar to HPub but it’s a closed standard. The Adobe Digital Publishing Suite is closed and proprietary as well. These two also demonstrate the need of such solutions, in contrast with the low-fidelity ePub format.

The reason is simple: if there’s a text in HTML, the moment I choose to not render the content as I desire, I’m getting exactly what I got with ePub: text with some semantic tagging.

See what the HTML5 specification says:

“User agents are expected to support CSS”

Uh? Doesn’t that mean…? Wait:

“The term expected in this section has the same conformance implication as the RFC2119-defined term must”

Done. This is the difference. HTML again goes to great lengths saying that the content is flexible, that the rendering can be manipulated and so on. But everything about rendering is a “must”.

HTML is already way beyond the potential of ePub, because it mandates rendering but, as it already happens with tools like Readability, this doesn’t mean a reader can’t access the text in a more readable way ignoring the presentation as defined by the author. This is why I can’t agree on the complete bias toward readability that EPub has.

Then again: I’m not against having readable text for everyone, but if that was the case then we wouldn’t have these amazingly designed magazines and books you can find today. Flexibility is critical, and mandating a rendering mode is the important piece to allow this flexibility.

The HPub standard

This clear dismissal of visual design as a requirement, is one of the pieces holding back a design revolution in the digital publishing industry. That’s exactly why I defined with Alessandro Morandi and Marco Natale as the co-founders of the Baker Framework, an open standard called HPub.


While we aren’t a standardized body, we tried to keep the process to define the HPub standard as open as possible by contacting people working in the field and having an open discussion on GitHub. We wanted a format that allowed the use of HTML as foundational and added the minimum set of elements to package it up as a publication, either book, magazine or else.

One of the driving forces for the standard was the ability to be as HTML based as possible. HPub at its core is like a HTML minisite, zipped and with a metadata file added, book.json. This means that creating a HPub is exactly the same as creating a static website. The implications of this are numerous, beginning with the ability of using any existing tool to design and develop them.

The beauty of this solution is that at its core it’s just HTML, and even without the specific features of HPub that make it a book, it’s a website and it’s browsable on the web as-is. With specific responsive techniques (media-queries) it’s possible to have a properly formatted book in HPub on iPhone, iPad and the same thing online. Nothing new: we just inherit form the existing and actively supported HTML5 standard.

This approach in our opinion leapfrogs anything else because instead of defining a new standard like ePub does, we just make use of an existing one as much as possible, adding a single small file to manage the peculiarities of publications.

The book:// protocol

One of the key elements in the publishing industry is a way to identify a specific publication, and that’s done through the ISBN code. In the digital world, we already have unique identifiers that refer to a single resource. They are the URLs – or, well, URIs, Uniform Resource Identifiers.


As any other part of HPub, we didn’t have to invent anything new. HPub uses URIs to identify uniquely publications, without any additional constraints, since the system is already well estabilished and standardized. On top of that, URIs convey way more information than ISBN and can be used to provide additional features, like a way to link, buy or download the book.

As it happens with other protocols, the book:// protocol is just a form of URI that can be used to trigger automatic discovery and download of publications, or be used at its minimum just to identify one book from another.

The experience ecosystem

One part where the current publishing revolution is way behind the curve is about the ecosystem around the reading experience.


The basic action is of course reading, but immediately after we can see that reading is easily accompanied by the act of annotating. Current software platforms are incredibly behind even in these simple actions. They can do very little beyond selecting texts with a couple of colors and adding a typed note. Images, cross-references, connections… we have no luck with these.
These two actions are also the only two that are inherently private. All the others are, in one way or another, social.

But of course, the ecosystem doesn’t stop there. The first step is actually the buying moment, and that’s pretty much out there. Of course, that’s hardly a surprise, since it’s where companies make money.

To buy however there’s the find issue, because everything starts with discovery. Online stores aren’t that good at that, they are just endpoints to buy items.

The sequence of findingbuyingreading and annotating is the basic required end-to-end service and experience that needs to exists, and when we observe this small chain we can notice how many pieces are already missing. This is the chain existing today in the main players on the market, namely Amazon Kindle and Apple iBooks.

But the ecosystem is of course more complicated than that.

First of all, there are three other big moments connected to the reading experience. The first one is of course discussing. Books and magazine are very often starting point for discussions, conversation and debates. There are people that even read books just to be able to participate in social conversations about them. And still, discussing is the first missing element that doesn’t have yet an ad-hoc platform or solution, using instead the existing ones.

Annotating as referenced above has however two moments in it, one of which starts from the personal annotation but is intended to be shared in some way: it’s the quoting part. While you hardly would share your notes, it’s likely you would love to share quotes of a book or magazines. Maybe even pictures from them. Again unfortunately, quoting is barely implemented in the Kindle service, and they even made private the limited feature page they once had. Instead of creating something a user could be proud of, there’s a white bland page with a couple of links and shares. Ouch.

The last part of the experience is the gifting and borrowing/lending. Both of them involve two people instead of one, but while we can fit gifting inside the buying experience, borrowing is actually a very different action.

I’ve just summarized a potential rich book ecosystem, and already you can see that the industry here has barely touched the surface and there are loads of functionalities that can be done to create a rich experience.


As you can see from this long – but brief – overview the market right now is open and there’s a lot of space for the publishing industry to grow and embrace this new digital world, from standards to technology to experiences. I built Baker with two friends to demonstrate this chance, but there’s a lot more out there to create and improve.

Article prepared from a presentation at eBook Lab and following university lecture, see the complete deck on Slideshare here.