Any device that can display text on a screen may act as an e-reader, but specialized e-reader designs may optimize portability, readability (especially in sunlight), and battery life for this purpose. A single e-reader is capable of holding the digital equivalent of hundreds of printed texts with no added bulk or measurable mass.
An e-reader is similar in form to a tablet computer. A tablet typically has an LCD screen capable of higher refresh rates which makes it more suitable for interaction. Tablet computers also are more versatile, allowing one to consume multiple types of content as well as create it.
The main advantages of e-readers are better readability of their screens, especially in sunlight, and longer battery life. This is achieved by using electronic paper technology to display content to readers. Commercially sold electronic paper is mostly available in black and white (16 shades of gray). The Sony Librie, released in 2004 and the precursor to the Sony Reader, was the first e-reader that used electronic paper. The first color e-reader on the market was the Ectaco jetBook Color, with a 9.7" screen, and its muted colors have been criticized.
Many e-readers can use the internet through Wi-Fi and the built-in software sometimes provides a link to a digital OPDS Library or e-book seller, allowing the user to buy, borrow, and receive digital e-books free through this library or seller. In this way, the books owned by the user are managed in the cloud, and the e-reader is able to download material from any location. An e-reader may also download material from a computer or read it from a memory card.
Many of the major book retailers and third-party developers offer free (or premium or ad-paid) e-reader applications for desktops, tablets and mobile devices, to allow the reading of eBooks and other documents independently of dedicated e-book devices.
Research released in March 2011 indicated that e-books and e-readers are more popular with the older generation than the younger generation in the UK. The survey carried out by Silver Poll found that around 6% of over-55s owned an e-reader compared with just 5% of 18-to-24-year-olds. According to an IDC study from March 2011, sales for all e-readers worldwide rose to 12.8 million in 2010; 48% of them were Amazon Kindles, followed by Barnes & Noble Nooks, Pandigital, Hanvon and Sony Readers (about 800,000 units for 2010).
In 2012, there was a 26% decline in sales worldwide from a maximum of 23.2 million in 2011, although Kindle sales remain strong. The reason given for this "alarmingly precipitous decline" is the rise of more general purpose tablets that provide e-book reading apps along with many other abilities in a similar form factor. In 2013, ABI Research claimed that the decline in the e-reader market was due to the aging of the customer base.
An idea similar to that of an e-reader is described in a 1930 manifesto written by Bob Brown titled The Readies, which describes "a simple reading machine which I can carry or move around, attach to any old electric light plug and read hundred-thousand-word novels in 10 minutes". His hypothetical machine would use a microfilm-style ribbon of miniaturized text which could be scrolled past a magnifying glass, and would allow the reader to adjust the type size. He envisioned that eventually words could be "recorded directly on the palpitating ether".
- Amazon: Kindle, Kindle Touch, Kindle Paperwhite, Kindle Voyage
- Barnes & Noble: Nook, Nook Simple Touch, Nook GlowLight
- Bookeen: Cybook Opus, Cybook Orizon, Cybook Odyssey, Cybook Odyssey HD FrontLight
- Ectaco: JetBook
- Kobo: Kobo Touch, Kobo Glo, Kobo Mini, Kobo Aura, Kobo Aura HD
- Onyx: Onyx Boox M92, Onyx Boox i62ML
- PocketBook: PocketBook Touch, PocketBook Mini, PocketBook Touch Lux, PocketBook Color Lux, PocketBook Basic Touch
- Tolino: Tolino Shine, Tolino Vision
- Comparison of e-book readers
- Supporting platforms for e-book formats
- Open Publication Distribution System
- Ray, C. Claiborne (October 24, 2011). "The Weight of Memory". The New York Times. Q&A (column). p. D2.
- Falcone, John (July 6, 2010). "Kindle vs. Nook vs. iPad: Which e-book reader should you buy?". CNet. Retrieved January 26, 2013.
- "Ectaco jetBook Color E-ink reader". Trusted Reviews. Retrieved June 17, 2013.
- "E-book popularity set to increase this year". Retrieved 4 March 2011.
- "Nearly 18 Million Media Tablets Shipped in 2010 with Apple Capturing 83% Share; eReader Shipments Quadrupled to More Than 12 Million" (Press release). IDC. 10 March 2011.
- Tibken, Shara (December 12, 2012). "RIP e-book readers? Rise of tablets drives e-reader drop". CNet.
- Smith, Tony (25 January 2013). "Tablets aren't killing e‐readers, it's clog-popping wrinklies – analyst". The Register.
- Brown, Robert "Bob" (2009). Saper, Craig J., ed. The Readies. Literature by Design: British and American Books 1880–1930. Houston: Rice University Press. ISBN 9780892630226. OCLC 428926430. Retrieved 2012-12-06.
- Schuessler, Jennifer (2010-04-08). "Bob Brown, Godfather of the E-Reader". The New York Times. Retrieved 2012-12-06.
- Media related to E-book readers at Wikimedia Commons