Despite all the stuff about factories and workers, this novel is primarily about the way the decisions of a father (Gradgrind) play out in the lives of his children (Louisa and Tom). He experiments with their upbringing, depriving them of any understanding of emotions, the imagination, and basic morality. They turn into broken and wasted human beings. Almost everything else that happens in the novel comes from this central conflict.
Hard Times is a "canonical text." This means that it is one of a group of novels, poems, and pieces of drama that are almost universally acknowledged to be important pieces of literary. It's one of those books that's considered fundamental to the development of Western civilization. What is interesting, though, is that at the time when it was published, this novel could have been considered "popular fiction" as well. It was certainly what we would now call a bestseller, and its serialized publication (the what, now? Check out the "In a Nutshell" section to learn more) needed to emphasize the thrills and chills of its plot to get readers coming back for more.
The characters and plot are here to advance one main point: Utilitarianism sucks. This philosophy reduces complex human individuality, personality, and emotional life into a simplistic and useless statistical analysis. If you take away the messy business of the inner life of the mind and replace it with a Utilitarian robot brain, then you will leave a bunch of hopelessly disturbed people in your wake. The novel puts forth the idea that it is actually impossible to breed or educate the humanity out of humans. We need creativity and imagination to survive.