Perhaps the issues is with the software rather than the format. I use KOReader and it offers a number of tools for browsing through a book. Which is fantastic.

Perhaps the issues is with the software rather than the format. I use KOReader and it offers a number of tools for browsing through a book. Which is fantastic. Yet most of the software out there is incredibly linear (with the only exceptions being keyword search, table of contents, and maybe an index provided by the publisher).