Post ChatGPT, I found that I could turn passive chapters in books to summaries; but when I wanted to dive back in to them in parts where I found them interesting, I'd have to map from summary to source manually. Further, I couldn't switch to audio seamlessly.

This is an interface where you have on a chapter level, multiple levels of detailed summaries, bi directionally linked to source text on a paragraph level; the summaries are constrained to be linear/chronological as such. You can also switch to TTS anytime (and switch back to reading).

Please let me know if you find this useful, I personally really enjoy reading non fiction in this interface (sometimes fiction too).