If HTML/CSS (or more specifically, some HTML renderer) had somewhat better support for paragraph-level typography and column-by-column or page-by-page layout (that is, hyphenation, justification with proper paragraph composition, widow/orphan controls, better floating image positioning especially in a multi-column context, some ability to organize floating content both horizontally and vertically without using tables, page numbering and same-page footnote layout, etc.), then it would be a perfectly fine e-book format (or, for that matter, printed book format). Adding support for all the typographic features in modern fonts (small caps, uncommon ligatures, lower-case numbers, etc.) would be a nice plus, but wouldn't really be essential.<p>Unfortunately, as it is, the book printers of the 16th century were able to make more readable text layouts than can be easily done with HTML/CSS today. Instead, all the new HTML/CSS features are focused on whiz-bang, rather than getting the (text) basics right.