The heroine of this book reminds me of Kate Chopin's in The Awakening . She's not really likeable and she is selfish. She takes her kids with her to the country to get away from London high society and leaves them in the care of a nanny while she cavorts with a pirate, adventures on the high seas ensuing. She dresses like a man to aid her lover in his plans to get away with his piracy. She's his cabin boy. The theme is escape: to escape the stifling constraints imposed on females in urban society to find freedom in the countryside and fulfill the longings of her suffocated soul. The ending I think brings the plot to a respectable conclusion not withstanding Dona's recklessness. She does something cruel to a minor character at the end which left a bad taste in my mouth. One last point: I did not get the dynamics of their positions when they are fantasizing about or having sex.  It took away from my enjoyment of the plot.