any discussion of "what .epub supports" is dishonest dialog. because the truth is that different .epub viewer-programs "support" different subsets of the "official standard", and thus the _reality_ of the format is that it's one huge mess, a "standard" that's been embraced and extended to death, whenever it wasn't locked-down with d.r.m. to begin with. and that is exactly how the corporate publishers _want_ it. because they're trying to stave off the revolution that will short-circuit their cash-registers and ruin their business. so what are they doing with .epub? why, coming out with _a_3.0_version_, of course, the better to boggle you with. you think things were confusing and fragmented _before_? well let's throw audio and video into the mix too, because the last decade of the web _proved_ they cause infighting. throw in some javascript, and html5, maybe flash as well, in order to _ensure_ that e-books are a nasty experience. it's no accident that amazon outpaced i.d.p.f. even while using a format that was supposedly "inferior" to .epub... but the end-run is inevitable, so all i.d.p.f. can do is stall it. study the "history" all you want, most especially if you want to distract people from _the_future_. but if you want to go _forward_, we need _a_clean_break_ from crap like .epub... -bowerbird