2nd edition. This is a reflowable ePub format, ideal for reading the book on smartphones, ebook readers, or tablets. Unfortunately the ePub format limits layout and graphics placement options, so it's not as pretty as the printed book or the PDF version. For example, instead of glossary terms being defined in the margin of the page, in the ePub, unfamiliar words are hot-links to our web-based glossary. If you plan to read the book on a computer, or a higher resolution tablet (like a recent-model iPad), you might consider the PDF version instead.