Michelle Isenhoff

The Quick and Dirty Facts About Digital Books, Files, and Devices

If you’re new to the world of digital readers, no doubt you’re as overwhelmed as I was when I received my first Kindle. There are so many types of devices, countless reading apps, various file types, and lots of online retailers. So what goes with what? It can all be pretty confusing. Fortunately, sorting it out will start right here.


In this post, I’m not going to compare products or tell you what to buy. But I will give an overview of some of the brands and products that have endured during the eight years I’ve been self-publishing.
Digital reading devices can be divided into three broad categories: Phones, tablets, and E-readers. Phones don’t require much explanation so I won’t get into them. But since they require an app to read with, I will touch on a few of the more common ones below. Tablets work much like a phone, with the ability to access the internet and do much more than simply display book text. Most (if not all?) utilize reading apps, and each brand has an associated or default app (i.e., Kobo app for Kobo devices, Google Play app for Android devices, Kindle app for Kindle Fire, etc.), but it is often possible to switch those up (i.e. Kindle app for Android devices). E-readers are simpler devices, usually used strictly for reading. Internet functionality is limited primarily to purchasing and downloading books. But before I get into these more specifically, let’s tackle book files.

File formats

Ebooks come in three file formats: EPUB and MOBI. Most of the time, you’ll be purchasing books from the retailer who sold you your device, and they’ll download automatically, making an understanding of file formats irrelevant. However, ebooks can be obtained from lots of other sources. For example, Project Gutenberg makes many public domain titles freely available for download. Select titles are given away on sites like BookFunnel or Prolific Works. And establishing a relationship with a favorite author might even mean he or she will send you a review file via email, which you can then sideload onto your device. In all these instances, it’s important to know which file format works with your device or app, so let’s take a closer look at each.
MOBI: It will simplify everything when you understand that MOBI files are strictly for Kindle devices. Why Amazon decided they needed to deviate from the norm and create files that are incompatible with other devices (unless you install the Kindle app), I don’t know, but it’s worked for them. They’ve created a dynasty, capturing something like 80% of the digital market last I heard. If you have any Kindle product, you will need MOBI files, which means you’ll do all your shopping on Amazon (which is probably the reason for their exclusive file format).
EPUB: Every other brand and retailer utilizes the EPUB file format. ALL of them. (Older generations sometimes have oddball formats, but EPUB has become the modern standard.) Which means a book purchased on Kobo device can theoretically be read on a Nook, which is put out by Barnes and Noble (though I’ve never tried this, since I only own a Kindle). If you read on anything besides a Kindle or Kindle app and you are given a choice of formats, choose EPUB.
PDF: On rare occasion, you may see this third option available. Some e-readers do support PDFs, but these files don’t flow nicely. They have fixed page formatting, which means the entire page is visible on the screen at once. This makes them great for viewing on a large screen like a laptop (which they are primarily used for), but not so nice for e-readers. The type can get very, very small. I’d recommend this file format only if you intend to read on a computer.

Popular Vendors

Let me finish up by giving a list of the major players on the current digital scene, relayed in the order of my own particular knowledge:
Amazon: Does this mammoth need an introduction? They sell ebooks by the millions, have free Kindle apps available for most competitor’s phones and tablets, and sell a variety of Kindle e-readers as well as the popular Kindle Fire tablets. They are definitely the heaviest hitter on this list and the place I sell the vast majority of my books.
Barns and Noble: Another big name, B&N came out with the Nook, one of the earliest e-readers and which is still popular today. They also have a huge digital bookstore, their own free Nook app, and a variety of tablets and e-readers. They come in second for my ebook sales.
Kobo: Based in Canada, Kobo has been gaining traction in overseas markets. They have a large selection of ebooks and their own free Kobo app and line of tablets and e-readers. I have also listed my books with Kobo directly, though I don’t make much here.
Apple: We can’t leave out iBooks. One of the digital kings, Apple captures a significant share of the ebook pie, though I do find their store the least user-friendly. But then, I’m usually searching it on a Dell laptop. I’m not really part of the Apple world, and have listed my books with them through a third party, so I’m just going to point you to their main store and let you browse books, apps, and devices on your own.
Android: I’m not very familiar with this one, either. I do know that Google Play is their official app store, and that’s a name I see often. Google Play has definitely been making inroads in the ebook world and has landed among the big five online ebook distributors. I have not, however, listed my books here.
I’ve named the giants, but there are a bazillion other reader apps and vendors out there. Now that you’re armed and dangerous, get out there, take a look around, and jump into the world of digital print!
Note: This has consistently been one of the most-read posts on my website. Originally written in 2011, it was desperately in need of an overhaul, which I completed in 02/19.

The Quick and Dirty Facts About Digital Books, Files, and Devices

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