When Paul Biba, a Bernardsville, New Jersey, lawyer, finds himself stuck waiting, he likes to pull out his Nokia E61i cellphone and read one of the 20 or so books he usually stores on it.

The virtual bookshelf in his pocket currently has science fiction such as Falling Free by Lois McMaster Bujold, all the novels of Anthony Trollope and Charles Dickens, and more. “Once you get used to having books with you, you get used to reading in places where it never occurred to you," he explains.

Phone book: Reading is easy on the Nokia E61i.

The bright virtual pages, along with other advantages such as weight, capacity and a built-in reading light, are gradually drawing readers. The International Digital Publishing Forum, a trade group for electronic book-sellers, estimates that retail sales of e-books grew to $8.1 million (about Rs32.5 crore) in the second quarter of 2007, up from $4 million a year earlier.

For reading an electronic book, it is hard to beat the Sony Reader. Sony’s thin, nine-ounce (about 250g) tablet comes with a high-resolution black-and-white screen that uses a tiny amount of power, prolonging its battery life. The Sony Reader is intended for moving through a book, offering buttons that let you flip pages with one hand and software that formats the text to fit the screen (cellphone readers need to use a cumbersome number pad, which is designed for calling, not browsing).

The drawback is the $299 investment for the Sony Reader. Cellphones, on the other hand, are a sunk cost. You already bought one for making calls, tracking email and messaging friends.

Most of the advanced cellphones, as well as personal digital assistants with larger screens and laptops, can do a good job of displaying words with special “reader" software. Mobipocket (mobipocket.com), a French company owned by Amazon.com, and eReader.com, a division of Motricity, distribute two of the most popular applications.

But there are many options. Fictionwise.com, a bookseller that supports many formats, sells some new novels as “multiformat" packages that let users choose among 10 readers from companies such as Microsoft, Franklin or Adobe. Microsoft’s Reader (www.microsoft.com/reader), for instance, works only with versions of Windows running on PCs or PocketPCs. Adobe distributes a PDF reader for most major platforms, including cellphones, which runs the Symbian OS found most commonly on Nokia phones.

The basic readers are available free, but some companies offer enhanced versions for a price. The “pro" software from eReader.com costs $9.95 and offers a bundled dictionary and more sophisticated features such as auto scrolling. There are also open source packages such as Plucker (plkr.org) available free. Many people install several readers so they have at least one that matches the format of the book they want to read.

Advanced cellphones with large screens, such as the Palm Treo or the Apple iPhone, can usually display e-books formatted in basic standards such as the PDF or HTML, but their controls are not optimized for long texts (the drawback: many cellphones have bright displays with backlighting that drain batteries faster).

It is only a matter of time before users create tools specifically for the iPhone, said Michael Hart, the founder of Project Gutenberg, a repository of e-books no longer under copyright protection. “The iPod was only out one week before we had e-book readers running on them, so it will be no surprise if there are multiple sets of programs, readers and formats for the iPhone," he said.

Indeed, Stephen Pendergast, the chief technology officer at Fictionwise.com, said his company is trying several formats, including narrow PDF files with margins tuned to the screen’s width.

For now, books can be downloaded from a variety of commercial and free websites. Some, such as Mobipocket and eReader, offer text in their proprietary format, while Fictionwise and others sell text in many different formats. Some, but not all, of the commercial books are copy protected. Mobipocket’s software, for instance, scrambles a file so the book can only be read on authorized machines. While the number of different formats can be confusing, it is simple to install multiple readers on the same device so there is always the right one available for a book.

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