Not sure this will answer your question. I you need to create an index of your book as a separate file by supplying a list of keywords, IndexMatic 2 could help you. The script is currently provided in BETA:
HOW TO DO:
1) Open the InDesign book (you don't need to open the underlying documents)
2) Run IndexMaticBeta.jsx from the script panel.
3) In the "Scope > Document(s)" listbox, select "Active Book".
3) In the "Search Mode > Mode" listbox, select "Query list".
4) Press "Edit Queries...".
5) In the "Edit the queries" dialog, press "Load from a file..." if your keywords are already stored in a file. Otherwise, enter your keywords line by line, e.g.:
IndexMatic also supports regular expressions and "entry rewriting" features. To specify a keyword as a regex, simply embed it in slashes:
By default, every key/query comes out unchanged as a final entry. But you can rewrite and/or regroup entries using the ' =>' operator:
/apples?/ => apple
butterfly => InDesign
buttterflies => butterfly
/(dog|cat)s?/ => pet
6) Still in the "Edit the queries" dialog, press "OK" to validate your queries.
7) In the "Default options" zone, check/uncheck the options you need: Case sensitive, Whole Word, Generic Space. "Generic Space" means that any space supplied in a query will match against all blank characters, including InDesign special spaces.
8) In the "Entry Case" listbox, select "Title case" to get the final entries title case formatted.
9) In "Page Report", configure the page separator and the page range options as desired.
10) Press "Run".
Tell me. (I'm curious to know how IndexMatic deals with a 1000 pages book!)