After many years of hype and unfulfilled promise, the market for electronic books and reading devices has recently grown significantly. ...demand continues to increase and the implications are beginning to be felt in several areas. Publishers have made progress in their efforts to overcome the technical and financial challenges that this field presents and among many companies Google, Amazon, Sony, and Apple are now making millions of digital books available through a variety of platforms and devices. Some people may still find these products too expensive, impractical or unpleasant to use, but demand continues to increase and the implications are beginning to be felt in several areas.

Digital books are not a panacea--there have been difficult moments for companies and users alike. There are numerous, quickly evolving formats, but none is ideal. They range from freeware systems like EPUB and eReader to propritary formats such as Amazon's AZW and Microsoft's LIT. Most devices render content only in black and white or grayscale, and though this lends to readable text, the quality of charts, tables, graphs and images varies. Some systems require always-on Internet connections, so when that connection is lost or a server crashes, the result can be loss of access or customer data. Others require software downloads that are painfully slow for users without high speed connections. And, since the books are licensed (not owned by the end user) companies can delete books from devices without notice. For example, some users of Amazon's Kindle experienced this phenomenon over the summer after the book seller admitted that it distributed an unlicensed version of Orwell's 1984: the company (probably not intending the irony) reached into its users devices and deleted the book.

For publishers, this has been one of the few growth areas in their industry recently. Many digital media service companies offer complete systems for converting and distributing publisher titles. Ebrary and Books 24×7, for example, license books only to libraries and other organizations for their publisher partners. VitalSource has become dominant in the fields of dentistry, nursing and law by marketing directly to students. They claim that over a billion ebooks have been distributed with their system. Some university presses like Oxford and Princeton are offering books in ebook reader formats. Other publishers are joining together to create their own platforms and products. CourseSmart, a consortium of major textbook companies founded in 2007, offers thousands of textbooks used in hundreds of courses in a high quality proprietary ebook format on a common platform.

Customers now have many product options available to them. Previously, text and audio ebooks were designed to be downloaded to or accessed through desktop or laptop computers, then iPods and smart phones. Now there are at least 16 ebook readers on the market with more on the way.

Many teachers like the way that digital formats can extend course material. In addition to the images and diagrams of print versions, many ebooks contain hyperlinks to citations or multimedia resources. Some of the ebook platforms are linked to course management systems' wikis, assignments, or quizzes. VitalSource's free Bookshelf application allows for cutting and pasting, sharing notes and customizing views. Just as you might highlight or write a note in the margin of a printed book, some ebook readers, like the Barnes & Noble Nook and Sony Reader, have a touch screen and/or stylus for writing notes; the Kindle and others have a keyboard for this. Also, the traditional index is replaced with search tools.

If the features function well, they can allow for a deeper engagement with the material and strengthen media literacy, writing and editorial skills.Since students learn in different ways with ebooks they may need time to adjust to these features. If the features function well, they can allow for a deeper engagement with the material and strengthen media literacy, writing and editorial skills. Assignments need to leverage the strengths of ebooks, and recognize that tools like search technology can lead to superficial, non-critical thinking. Therefore, ebooks might not be suited to every situation.

The impact on libraries varies. Many are expanding their free ebook offerings to save money on space and staffing and to meet growing demand. Patrons of the nearly 9,000 public and college libraries serviced by OverDrive Inc. can now download books to Sony's ebook readers. In an extreme case, the Boston Globe reported recently that Cushing Academy, a 144-year-old school west of Boston, has decided to discard and give away most of the 20,000 print books in their library. The school's new virtual library will contain laptop-friendly study carrels and a coffee shop. Students will have access to one of 18 ebook readers or else use their computers to access assigned material.

But not all ebooks will be available to all library users. Many publishers, including Simon & Schuster and Macmillan, don't allow public libraries to lend digital versions of their titles, fearing that this would hurt sales in any format. Also, some electronic resources don't comply with accessibility standards for technologies used by library patrons with disabilities. Furthermore, libraries may have to buy, lend and maintain ebook readers so that members can access books that are only available in digital form. On-demand book printing machines that can produce paperback books quickly and cheaply are an option that some institutions such as the University of Michigan Library and the New Orleans Public Library are exploring to improve access.

The ebook market will continue to evolve as competition among reader device manufacturers, publishers and digital media companies intensifies. It will also be impacted significantly by the anticipated Google Book Search settlement, which could make available millions of out-of-print and orphan works (books not yet in the public domain and with unknown rights ownership). Over the next few years we can expect more products to choose from, lower prices and improved features like color displays. But evaluating options will require a significant time investment for individual users, educators and librarians.