An e-book for every device

When you purchase an e-book at holartbooks.com, we want to make sure you'll always be able to read your book, on whatever device you own, now and in the future. So, rather than locking you into a single file format, every Hol e-book purchase includes the book in three popular, DRM-free (encryption-free) file formats: EPUB, MOBI, and PDF. With these three formats, you'll be able to read your Hol e-book on any device you choose.

The differences between the file formats are pretty simple.

PDFs are static pages. They most often share the same layout and design as the book's print edition, though ours are also augmented with external links to web pages where cited, and internal links (or bookmarks) in the table of contents to better navigate around the book. And when the book includes images, we make every effort to include them in color in the PDF, even if they were reproduced in black & white in the print edition. For reading on a laptop or desktop computer, or where the design of the book is important, PDF can be the best way to go. But because PDF pages and type are a fixed size, they are not always optimal for e-readers or smartphones, even when those devices can handle the file.

EPUB and MOBI are dynamic pages. These two file formats are both versions of the book in re-flowable form. This means that the text can be enlarged or reduced, the font style and color can be changed, and the scale and design of the page can be better optimized for all varieties of screen sizes or technologies—all only limted by the reading application you use. The trade off to these features is that the books lack the distinctive design we've become familiar with in paper books because the design is controlled more by the e-reading application and the reader (you) than by the publisher. For a publisher, the design that's important in re-flowable e-books is not choosing a particular typeface, page size or margin; it's determining the ordering of content, the relative strength of elements and navigability.

FInally, the difference between EPUB and MOBI is primarily one of device support. Currently, Amazon's Kindle and many Windows-based devices rely on MOBI, while most others, including Apply, Barnes & Noble, Sony and Kobo, support EPUB. (And if you were wondering: EPUB is an open standard constantly undergoing improvement by the top players in the industry, so, when given a choice, this is our preferred format.)