Job it out to a localization professional.
No, but seriously, your question sounds a bit like "I'm trying to improve my designs... what should I do?" Too vague for me to make any constructive suggestions, and I'm a (drumroll) localization professional. Fill in some workflow details for us - while there aren't that many translation-industry folks hanging around here, the regulars have a mind-boggling amount of general collective workflow expertise. The "most efficient way to do this" depends mostly on what "this" you have to do, and with whom you have to do it.
Thanks for your reply. Sorry for not being clearer in my initial question.
The book has already been translated. My question is is how to typeset the word file into the existing Indesign layout the fastest.