E-book

An electronic book (also e-book, ebook, electronic book, digital book) is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital. The Oxford Dictionary of English defines the e-book as "an electronic version of a printed book," but e-books can and do exist without any printed equivalent. E-books are usually read on dedicated hardware devices known as e-Readers or e-book devices. Personal computers and some mobile phones can also be used to read e-books. 
History
In 1971, Michael S. Hart was given extensive computer time by the operators of the Xerox Sigma V mainframe at the University of Illinois. Seeking a worthy use of this resource, he created the first ebook by typing the United states Declaration of Independence into a computer. Project Gutenberg was launched afterwards to create electronic copies of more books.
One early e-book implementation was the desktop prototype for a proposed notebook computer, the
Dynabook, in the 1970s at PARC: a general-purpose portable personal computer capable of displaying books for reading.
Early e-books were generally written for specialty areas and a limited audience, meant to be read only by small and devoted interest groups. The scope of the subject matter of these e-books included technical manuals for hardware, manufacturing techniques and other subjects. In the 1990s, the general availability of the internet made transferring electronic files much easier, including e-books.
Numerous e-book formats, view comparison of e-book formats, emerged and proliferated, some supported by major software companies such as Adobe with its PDF format, and others supported by independent and open-source programmers. Multiple readers followed multiple formats, most of them specializing in only one format, and thereby fragmenting the e-book market even more. Due to exclusiveness and limited readerships of e-books, the fractured market of independents and specialty authors lacked consensus regarding a standard for packaging and selling e-books. In 2010 e-books continued to gain in their own underground markets. Many e-book publishers began distributing books that were in the public domain . At the same time, authors with books that were not accepted by publishers offered their works online so they could be seen by others. Unofficial (and occasionally unauthorized) catalogs of books became available over the web, and sites devoted to e-books began disseminating information about e-books to the public.
U.S. Libraries began providing free e-books to the public in 1998 through their web sites and associated services, although the e-books were primarily scholarly, technical or professional in nature, and could not be downloaded. In 2003, libraries began offering free downloadable popular fiction and non-fiction e-books to the public, launching an e-book lending model that worked much more successfully for public libraries.The number of library e-book distributors and lending models continued to increase over the next few years. In 2010, a Public Library Funding and Technology Access Study found that 66% of public libraries in the U.S. were offering e-books, and a large movement in the library industry began seriously examining the issues related to lending e-books, acknowledging a tipping point of broad e-book usage. However, some publishers and authors have not endorsed the concept of electronic publishing, citing issues with demand, piracy and proprietary devices.
As of 2009, new marketing models for e-books were being developed and dedicated reading hardware was produced. E-books (as opposed to ebook readers) have yet to achieve global distribution. In the United States, as of September 2009, the Amazon Kindle model and Sony's PRS-500 were the dominant e-reading devices. By March 2010, some reported that the Barnes & Noble Nook may be selling more units than the Kindle.
On January 27, 2010 Apple Inc. launched a multi-function device called the iPad and announced agreements with five of the six largest publishers that would allow Apple to distribute e-books.The iPad includes a built-in app for e-books called iBooks and the iBooks Store.
In July 2010, online bookseller Amazon.com reported sales of ebooks for its proprietary Kindle outnumbered sales of hardcover books for the first time ever during the second quarter of 2010, saying it sold 140 e-books for every 100 hardcover books, including hardcovers for which there was no digital edition. By January 2011, ebook sales at Amazon had surpassed its paperback sales. In the overall U.S. market, paperback book sales are still much larger than either hardcover or e-book; the American Publishing Association estimated e-books represented 8.5% of sales as of mid-2010, up from 3% a year before. In Canada, the option of ebook publishing took a higher profile when the novel, The Sentimentalists, won the prestigious national Giller Prize. Owing to the small scale of the novel's independent publisher, the book was initially not widely available in printed form, but the ebook edition had no such problems with it becoming the top-selling title for Kobo devices.

Comparison to printed books

 

Advantages

Over 2 million free books are available for download as of August 2009. Mobile availability of e-books may be provided for users with a mobile data connection, so that these e-books need not be stored on the device. An e-book can be offered indefinitely, without ever going "out of print". In the space that a comparably sized print book takes up, an e-reader can potentially contain thousands of e-books, limited only by its memory capacity. If space is at a premium, such as in a backpack or at home, it can be an advantage that an e-book collection takes up little room and weight.
E-book websites can include the ability to translate books into many different languages, making the works available to speakers of languages not covered by printed translations. Depending on the device, an e-book may be readable in low light or even total darkness. Many newer readers have the ability to display motion, enlarge or change fonts, use Text-to-speech software to read the text aloud for visually impaired, partially sighted, elderly or dyslectic people, search for key terms, find definitions, or allow highlighting bookmarking and annotation. Devices that utilize E Ink can imitate the look and ease of readability of a printed work while consuming very little power, allowing continuous reading for weeks at time.
While an e-book reader costs much more than one book, the electronic texts are at times cheaper. Moreover, a great share of e-books are available online for free, minus the minimal costs of the electronics required. For example, all fiction from before the year 1900 is in the public domain. Also, libraries lend more current e-book titles for limited times, free samples are available of many publications, and there are other lending models being piloted as well. E-books can be printed for less than the price of traditional new books using new on-demand book printers.
An e-book can be purchased/borrowed, downloaded, and used immediately, whereas when one buys or borrows a book, one must go to a bookshop, a home library, or public library during limited hours, or wait for a delivery. The production of e-books does not consume paper and ink. The necessary computer or e-reader uses less materials. Printed books use 3 times more raw materials and 78 times more water to produce. Depending on possible digital rights management, e-books can be backed up to recover them in the case of loss or damage and it may be possible to recover a new copy without cost from the distributor. Compared to printed publishing, it is cheaper and easier for authors to self-publish e-books. Also, the dispersal of a free e-book copy can stimulate the sales of the printed version.

Drawbacks

Ebook formats and file types continue to develop and change through time through advances and developments in technology or the introduction of new proprietary formats. While printed books remain readable for many years, e-books may need to be copied or converted to a new carrier or file type over time. Because of proprietary formats or lack of file support, formatted e-books may be unusable on certain readers. PDF and epub are growing standards, but are not universal.
Not all books are available as e-books. Paper books can be bought and wrapped for a present and a library of books can provide visual appeal, while the digital nature of e-books makes them non-visible and intangible. E-books cannot provide the physical feel of the cover, paper, and binding of the original printed work. An author who publishes a book often puts more into the work than simply the words on the pages. E-books may cause people "to do the grazing and quick reading that screens enable, rather than be by themselves with the author's ideas". They may use the e-books simply for reference purposes rather than reading for pleasure and leisure. Books with large pictures (such as children's books) or diagrams are more inconvenient for viewing and reading.
A book will never turn off and would be unusable only if damaged or after many decades. The shelf life of a printed book exceeds that of an e-book reader, as over time the reader's battery will drain and require recharging. Additionally, "As in the case of microfilm, there is no guarantee that [electronic] copies will last. Bits become degraded over time. Documents may get lost in cyberspace...Hardware and software become extinct at a distressing rate." E-book readers are more susceptible to damage from being dropped or hit than a print book. Due to faults in hardware or software, e-book readers may malfunction and data loss can occur. As with any piece of technology, the reader must be protected from the elements (such as extreme cold, heat, water, etc.), while print books are not susceptible to damage from electromagnetic pulses, surges, impacts, or temperatures typically found in automobiles on a hot day.
The cost of an e-book reader far exceeds that of a single book, and e-books often cost the same as their print versions. Due to the high cost of the initial investment in some form of e-reader, e-books are cost prohibitive to much of the world's population. Furthermore, there is no used e-book market, so consumers will neither be able to recoup some of their costs by selling an unwanted title they have finished, nor will they be able to buy used copies at significant discounts, as they can now easily do with printed books. Because of the high-tech appeal of the e-reader, they are a greater target for theft than an individual print book. Along with the theft of the physical device, any e-books it contains also become stolen. E-books purchased from vendors like Amazon or Barnes & Noble.com are stored "in the cloud" on servers and "digital lockers" and have the benefit of being easily retrieved if an e-reading device is lost. Not all e-booksellers are cloud based; if an e-book is stolen, accidentally lost, or deleted, in the absence of a backup it may have to be repurchased.
The display resolutions of reading devices are currently lower than those of printed materials and may cause discomfort due to glare on the screen or difficulty holding the device. Due to digital rights management, customers typically cannot resell or loan their e-books to other readers. However, some Barnes & Noble e-books are lendable for two weeks via their 'LendMe' technology. Additionally, the potential for piracy of e-books may make publishers and authors reluctant to distribute digitally. E-book readers require various toxic substances to produce, are non-biodegradable, and the disposal of their batteries in particular raises environmental concerns. As technologies rapidly change and old devices become obsolete, there will be larger amounts of toxic wastes that are not easily biodegradable like paper..
Reading devices for e-books in a reflowable format such as EPUB may display page numbers, but these numbers change from device to device depending on factors such as the size of the display and the selected font size. This makes them unsuitable for citation purposes. To remedy this problem, Amazon Kindle e-books contain what are called "location numbers", that is, numbers in the margin of the electronic text that indicate where the corresponding page begins in the printed version of the book.
Use of an e-book reader is disallowed on commercial airliners during takeoff and landing.

Digital rights management

Anti-circumvention techniques may be used to restrict what the user may do with an e-book. For instance, it may not be possible to transfer ownership of an e-book to another person, though such a transaction is common with physical books. Some devices can phone home to track readers and reading habits, restrict printing, or arbitrarily modify reading material. This includes restricting the copying and distribution of works in the public domain through the use of "click-wrap" licensing, effectively limiting the rights of the public to distribute, sell or use texts in the public domain freely.
Most e-book publishers do not warn their customers about the possible implications of the digital rights management tied to their products. Generally they claim that digital rights management is meant to prevent copying of the e-book. However in many cases it is also possible that digital rights management will result in the complete denial of access by the purchaser to the e-book. With some formats of DRM, the e-book is tied to a specific computer or device. In these cases the DRM will usually let the purchaser move the book a limited number of times after which they cannot use it on any additional devices. If the purchaser upgrades or replaces their devices eventually they may lose access to their purchase. Some forms of digital rights management depend on the existence of online services to authenticate the purchasers. When the company that provides the service goes out of business or decides to stop providing the service, the purchaser will no longer be able to access the e-book.
As with digital rights management in other media, e-books are more like rental or leasing than purchase. The restricted book comes with a number of restrictions, and eventually access to the purchase can be removed by a number of different parties involved. These include the publisher of the book, the provider of the DRM scheme, and the publisher of the reader software. These are all things that are significantly different from the realm of experiences anyone has had with a physical copy of the book.