This is not what you think it is! ...but go ahead and let the book blindside you for the full effect.
People would ask me what I was reading, and I respond with a typical "oh, it's about a young gentleman who begins to reconsider approaching marriage when he notices a forlorn young woman who wanders the beach, pining for her lost lover..." And person who had posed the question would say "how nice." NO! This book has nothing to do the gentle, romantic, Victorian plot, setting, and mood that the author so carefully crafts before...well...you'll just have to read it to get the full effect, as I said. I suspect i was lulled into an unsuspecting state by trying to focus on the plot of the story, and I honestly still haven't sorted the ending out. If there's an answer to the mystery of the French Lieutenant's woman, I completely missed it. A mind-blowing, if frustrating reading experience.