While all readers allow you to side-load unprotected content, it’s important that they provide easy access to a large library of commercial books.

Library: Ebook readers can’t stand on the strength of their hardware alone.

Other features: While not required, features like waterproofing and Bluetooth audio can make a good e-reader great.

In other words, most specs are less important than how good the ebook reader feels in the hand.

Battery life and storage: Most of the readers promise battery life somewhere between six and eight weeks (depending on usage) and offer 8 GB or 32 GB of storage.

Six-inch screens are the most common size, as well as the most portable and likely to be pocketable, although newer readers pack larger screens into similarly sized bodies, which is a bonus.

Build quality and size: While most ebook readers are made of plastic, some feel better than others in your hands.

Anything lower will mean less crisp text and images.

Screen quality: We gave preference to devices with a pixel density of 300 dots per inch, the highest available in any ebook reader and what most models offer.

(Unlike tablets such as the iPad, ebook readers use a side-lighting system that provides a glow across the screen, rather than from behind it.) Because this feature is so prevalent, we didn’t test any readers without it.

Built-in lighting: Most e-readers provide their own light for reading in dark environments.

Kindle models compared