What is the theme of "Far From the Madding Crowd " by Thomas Hardy?

In Hardy's "Far From the Madding Crowd" there are several different themes at work. One of the obvious is of course the theme of unrequited love. This is shown by Gabriel Oak's love for Bathsheba, Boldwood's feelings for Bathsheba, and Bathsheba’s feelings for Sergeant Troy.  Beside this theme there is also the theme of catastrophe.  When Oaks, loses his sheep and eventually his farm is simply an occurrence of one bad event on top of another.As in all of Hardy's novels the concept of Class structure is also a recurring theme.  Many of the people in England at this time were moving from the country to the city as England became more industrialized.  Hardy was very concerned by the hierarchy.  This novel demonstrates

"how important social position was in England in the nineteenth century and of the opportunities that existed to change class, in either direction. In the beginning, Oak and Bathsheba are social equals: he is an independent farmer who rents his land, and she lives on her aunt's farm next door to his, which is presumably similar in value. The only thing that keeps her from accepting his proposal of marriage is the fact that she just does not want to be married yet. After Oak loses his farm and Bathsheba inherits her uncle's farm, there is little question of whether they can marry—their social positions are too different."