I'm just in a couple of chapters but it seems a very well-researched effort, current up to around 2005. I have also run across an interesting analytical article by Valeria Tsenova that examines Gubaidulina's use of mathematical proportions in structuring her music. So, armed with both these and whatever else I can discover, as well as my own examination of the music, we should be able to get a sense of this composer.
A few days ago I played the early Serenade for some friends and they really did not "get" what was going on in the music at all! So most listeners will likely need to be introduced to Gubaidulina's music in a fairly thorough way.
The great Russian cellist Mstislav Rostropovich wrote a foreword to the biography. Here is an unusual piece that she wrote for him, the Canticle of the Sun for cello, chamber choir and percussion based on a text by Francis of Assisi:
Let's end with a quotation from Gubaidulina that appears at the very beginning of the Kurtz biography:
It is not my desire to express an idea, but to give
expression to the spiritual form of an emotion
steeped in life itself.
It does not matter to me whether or not I am modern.
What is important is the inner truth of my music.
I have no doubt that women think and feel differently
than men, but it is not very important whether I am a
woman or a man. What matters is that I am myself and develop
my own ideas strictly toward the truth.