book indexes

[Chris Howell-Little]

This is sort of a general film scholarship question, but one that pertains
to Japanese film scholarship as well... anyway, as I've been digging
through my books for research papers at the end of the semester here, I've
been wondering, why do some books use an "index of names" and an "index of
films" in place of a general index?

I can think of more than few instances of this, including some incredibly
useful books (for instance, but not to single it out, Kyoko Hirano's "Mr.
Smith Goes to Tokyo"). I guess ultimately, indexes are a matter of
convenience for readers, and perhaps not a crucial component of a work.
Still, it's nice to be able to scan through the indexes to quickly find
material on general topics like jidaigeki, not just films and people.

Is the combination of those two indexes (of people and film) considered as
good or better than a general index? Is this more common in dissertations
turned into books?

-Chris