Always glad to see a new author taking a fresh take on old Hollywood. Unfortunately, this one doesn't shed a ton of light on Olivia De Havilland outside of what is typically known about her. She's a good girl, a great actress, wanted serious parts, admired Bette Davis, was hugely influential in the demise of the contract system, then retired to Paris to be a loving stay at home mom.
What was missing was what is in between the lines here. What was her relationship to Joan truly and how did that affect her life? Why did her marriages break up and how did she cope with this given her "good girl" status? Why was she so controlling of her image and what did they say about her as a person? It felt as though the author's proximity to and admiration for Olivia really limited her ability to dive deeper or provide true critiques of the star and her career.
That being said, this is a well-researched and source biography, just not what I would call compelling.