What major themes did the author focus on?

The Second Shift: Working Parents and the Revolution at Home was originally written by Arlie Russell Hochschild with Anne Machung in 1989 and revised in 2012 using more recent data.
The main theme is that working women end up working a "second shift" of unpaid labor in the home. The number of hours spent by married employed women on child care and housework are still almost two-thirds higher than the number worked by men, even when both partners are employed full-time.
The next theme of the book is the way women negotiate these disparities in a way that does the emotional work of protecting the male ego, as well as the emotional dynamics of relationships in which social conventions frame housework as feminine and earning money as masculine.
Another major theme is the book is the difference between egalitarian, transitional, and traditional ideologies of the family and gender, with members of the middle classes favoring egalitarian models and members of the lower class more likely to favor traditional models.
https://www.bls.gov/tus/charts/household.htm