I don't know if live interviews would have added anything to his book. I think we'd like to think they would. If these people were less than truthful in their memoirs, I doubt they'd have been any more forth coming in person, it's usually the same. To some extent, there's a lack of truthfulness in every one's memory- that's why it's always important to get two sides to a story. Also, people who don't want to be put on the spot usually refuse interviews, and it's hard to know if some of these people would have wanted to be put on the spot, or taken the chance. Olga A's memories were verbal- commited to paper by someone else, so that's essentially an interview. I think we want to believe that verbal memories would have opened up a whole new world, but in truth, they might not have been different than these people's memoirs. I think Massie used some memoirs in constructing the book, I maybe wrong, it's been forever since I read it. I think Massie did a good job for the time- today we have so much more access to info, and different viewpoints. Also, one reason Massie may not have used oral interviews is he didn't know the people involved and may have been hesitant about approaching them as he hadn't gotten his book published yet and didn't have all the connections he later had. He may have believed they didn't want to talk, or had already said what they had to say, it's hard to know.