In fact, this may already exist, but I’ll proceed anyways.
Some exposition…
I’m halfway finished with the 9th book in the absolutely massive Malazan Book of the Fallen decalogy by Steven Erikson. It literally has a cast of hundreds, with the central plots swirling around some 50-odd characters. Given my admittedly slow reading pace and the little time I allot myself per week to read, it’s taken me over two years to arrive where I am in the series.
The series itself is presented in such a way that the narrative follows perhaps 3 of the 6 major groupings of characters per book, so that you spend 1200 pages with half the characters, and don’t hear from them again for another 1200 pages. In the intervening pages, Erikson advances the other half of the story, introducing new subsets of characters you’re to blindly follow along with until their purpose in the overall story arcs is revealed.
To his credit, Erikson has to this point pulled it off. The series is packed with action and plot points that drive the stories forward, and each book has built to logical and usually surprising conclusion that leaves me eager for the next. I would LOVE to see the big wall somewhere where Erikson has everything mapped out. It’s truly astounding.
Anyways, to my point:
Over this vast number of pages, and long duration, and given Erikson’s huge cast of characters, places, and cultures, I’ve forgotten a lot. I’d love to see an integrated, hyperlinked, intelligent glossary in the eBooks. I’m currently reading the Kindle version of the book 9, and while it includes the same glossary as the print book, it’s a pain to access in both formats. If each character, place, and cultural name was hyperlinked to a succinct definition that provided what we know about that thing to that point in the story, I might spend less time mentally trying to piece things together from the surrounding context.
This probably isn’t the only work that could benefit from a tighter integration of the glossary. I’m almost positive the technology exists to enable it, and it would be one advantage of the format over the printed book.