[Peter Sorotokin]

Originally Posted by Nate the great

I think it's safe to assume that the indexes will be made during the ebook creation process. I would suggest that each index in an ebook be in a separate file(s). Given that Epub is basically zipped HTML, an index will likely consist of 1 or more links (that lead to other places in the ebook).

I think we should consider copying the behavior of Mobipocket indexes. A link in the title index doesn't lead to the respective title. Instead, it leads to the beginning of the entry containing the title. (I also agree with Igorsk about the need for multiple head words.) In the keyword index, each keyword will listed once, and link to a separate file consisting of links to each of the entries containing the keyword. The links won't lead to the keyword, but to the beginning of the entry.

So what you saying is that an entry in the index will look like this (assuming specialized XML mark-up for index).

<entry href="QU.html#queen">queen</entry>

And corresponding dictionary article like that (assuming XHTML for the content):

<dl id="queen">
<dt>queen<dt>
<dd>a female sovereign or monarch</dd>
</dl>

That would work on the syntax level, but I don't think a flat index file containing all words is going to cut it: it is still going to be too big.

Also, can we used any existing mark-up (e.g. XHTML or perhaps NCX) for index file? Should we just use XHTML-based index with some metadata marking it as such?

I'll think a bit more about it.