remember how, in chapter 2, we said that the table of contents should be hot-linked to the appropriate spots?
that is one type of link you'll need. there are several other types as well.
your system should also be able to make the jump to an internet site. most of the e-texts are quite old, so of course it's not like they have a bunch of internet url's in them; but every e-text will indeed contain a link to project gutenberg's website, so you must be able to execute links...
quite often there are places in an e-text that reference other parts of the e-text. in these cases, it's nice to have a hotlink close to (or on) that reference point that transports the reader directly to the place that is being referenced; it is convenient. your system should facilitate such linking, preferably making it happen automatically.
for instance, the beginning of this chapter has a reference to chapter 2. if a reader clicked on those words -- "chapter 2" -- they should automatically go to chapter 2.
(and likewise with each of the references to "chapter 2" here in this paragraph too.)