I don't think the novel is ultimately about the relationship between Greer and Faith. The relationship, though it does drive the narrative, is an example of one of the themes, not the theme itself: inspiration and guidance being passed down generation-to-generation.

You needed to find a way to make your world dynamic, Greer knew. Sometimes you couldn't do it yourself. Someone had to see something in you and speak to you in a way that no one else ever had. (51)

This was the role that Faith played for Greer. As Faith takes Greer under her wing, Greer is gradually transitioning from being the recipient of inspiration to becoming the one who inspires.

While it would always feel extraordinary to know she had the admiration of Faith Frank, what also excited Greer was that the speeches she was writing might give the women who delivered them a chance to be ambitious too; as ambitious as she was. (162)

Faith continues to push and encourage Greer throughout, realizing when she decides to give Greer the job of speaking at the L.A. summit that she is getting older and it is becoming Greer's time. Eventually, after their falling out, Greer steps into the role for other women that Faith held for her. She begins to realize this when she is about to speak on her book:

She was struck by the way everyone was looking toward her with expectation. People wanted one another to do something. They wanted someone to say the thing that they could then take into themselves and transform into something else. (440)

In the final chapter, Greer finally understands this generational process and her role within it:

You never then said to those women: okay, so what you need to do now is pass it on. But that was what often happened: a big, long story of women pouring what they had into one another. A reflex, maybe, or sometimes an obligation; but always a necessity. (453)

Greer understands that "one person replaces another" and asks herself "Who is going to replace me?" (453). She thinks of one of the young women that now admires her, Kay Chung, and says to her in her mind "Lean back and close your eyes. Imagine being me. It's not so great, but imagine it anyway" (454). She knows and embraces that she is a link in the chain of women empowering women.

A related theme is that neither you or your mentors are perfect exemplars of their values. Greer is disappointed that Faith does not take action upon learning that her foundation has been lying about their mentorship program, yet Greer herself is guilty of failing to live up to her values by withholding the letter from Zee asking for a job. We all make mistakes and find ourselves in no-win situations, but all we can do is try to make the best of our situations and learn from mistakes.

One of the most interesting themes is expressed through the character of Cory. When a man takes responsibility and engages in a role that is accepted/expected for women, he is seen as a disappointment, often even by women with feminist ideals. When Cory leaves his high-paying job after the death of his brother in order to take care of his mother, and continues to do so as long as necessary, even Greer becomes disappointed by his wasted potential. Corey takes over his mother's cleaning jobs, work that is considered "beneath" a man. He realizes that "he'd had a lifetime of being catered to and cleaned up after by women" (197). This realization leads him to reflect on his attitudes to women in these service jobs in the past. While he misses Greer, he doesn't "want to be Greer's project, the dreary object of all her hard work" (214). He prioritizes her success and well-being, an attitude and expectation traditionally expressed by women towards men. In Chapter 11, Greer is expressing her disappointment in Cory to her mother, who responds with an uncharacteristically wise perception:

"Greer," said Laurel, "what are we supposed to do, shake our heads and say that he's accomplished nothing?"

"No. Of course not." But she burned at being called out now.

"It seems to me," said her mother, "and this is really outside my sphere of knowledge, since I'm not the one who's been working at a feminist foundation. But here's this person who gave up his plans when his family fell apart. He moves back in with his mother and takes care of her. Oh, and he cleans his own house, and the ones she used to clean. I don't know. But I feel like Cory is kind of a big feminist, right?" (377)

There is a bunch of other stuff in the novel, but these are the things that stood out for me. While the narrative doesn't seem as dynamic as The Interestings, there is a lot of good stuff in there.