Interesting concept, but flawed. I've been reading through your concerns page, and it is very opinionated :-) Which is not bad per se, but I think in your case you just refuse to attack certain problems with Superbooks that are obvious.<p>"Strong layout" is just another name for fixed page layout. There is even no real difference to PDFs. PDFs work great for certain kinds of digital books like scientific books. BUT, I can only read them on my iPad Pro as on smaller screens PDFs don't work for me. Now, how does a Superbook address this? It doesn't. If its fixed layout is pleasant to read on my iPad Pro, then for sure it is not pleasant to read on my iPhone XS Max.<p>I agree that current e-books are not the answer yet. I would like something with the power of PDF fixed layout, but also reflowable. Something that can be created with a modern reimagining of Latex. That would be a Superbooks, in my opinion ;-)