In 1973 pianist Robert Sutherland was invited to help Maria Callas prepare for her comeback tour. He stayed, travelling with her for 15 months and then working with her in the studio until shortly before her death.
That's a strange text. I found it peculiar that a lot of things Callas allegedly said to the author I already had heard in her interviews. This raises some questions about how close Sutherland was to her and/or how much he remembers from their work. I am not implying the book is recycling old facts and statements but this definitely seems to be the case.