There were some gaps in the information about Nina. The  information I had managed to collect - discussions with those who were close to her, my own memories, notebooks - told only part of the story, and it was becoming obvious that, although the book was a biography, there would have to be some elements of fiction. However, that said, the actual structure of the book is based on fact, and, for events occurring after 1944, I was able to rely heavily on letters written to and by Nina - thankfully, she kept drafts of most letters she wrote.