This is the murkiest area at the start of the project with a new interview subject — seemingly innocuous questions may elicit an emphatic "I don't want to talk about that".

     Sex lives; abortions; incest; financial improprieties; murders & other mayhem; ... the fact that you know about somthing juicy doesn't mean that the subject area needs to be explored. This is probably the most critical part of the advanced research that you will need to do — what to stay away from. A few quick questions over the phone to the interview subject's siblings or spouse or children or caregiver or "significant other" will probably give you a pretty good idea of what they like to talk about and what they don't wish to hear a question about. (divorces, war wounds, business failures, victimizations, ... you get the idea)

     As much as you may be listening to what an interview subject may say so that you may formulate good followup questions, listen to how they are saying their answers. A talkative subject that suddenly provides terse, minimal responses; a subject who's voice grows progressively softer; a subject that stops cold and who's facial expression looks to be very uncomfortable — all signs that you have entered into an area that might be a serious problem for the subject. You might ask, gentily, if the subject would prefer to not talk about that topic. You might pause and suggest a break (it doesn't matter that you are only 5 minutes into a new one-hour tape ... take the break and provide the subject with some "space" for them to recover their composure or their inclination to continue being interviewed).

     You are likely to talk your way into some kind of psychological "mine field" at some point with some interview subject. You should always stay aware of where you are with the subject and have some kinds of exit strategies thought-out in advance; strategies that may permit you to continue with the interview session at some point in time. A session that is abruptly terminated by the subject because of their discomfort with a line of questions might never be restarted. It is best to always be listening carefully to gauge the ongoing comfort level of the subject; not just listening to the content in the subject's answers for clues to further questions..