Charles Dickens was born in Portsmouth in 1812 during the reign of King George III, but the reign he's most associated with is that of Victoria, who ascended the throne in 1837. When Dickens was 12, his father was imprisoned in a Debtor's Prison, the first major calamity in Dickens' young life. He was sent out to work to help keep the family (there were 8 children and he was the second oldest). His experiences working in a boot-black factory formed the genesis of many of his themes in his novels. Later, after various jobs in the legal field -- from which he gained a thorough knowledge of the law, and a dislike for lawyers and injustices against the poor, all of which permeated his work -- he became a political journalist for the Morning Chronicle in 1834.
It was around this time that he started writing novels, which in the fashion of the time were serialized in literary magazines on a monthly basis. In fact, in the early days Dickens often had several serials on the go at the same time. For example, he was finishing off The Pickwick Papers (his first novel) at the same time as starting on Oliver Twist. His novels were notable for their finely drawn characters, sometimes described as grotesque, with bizarre names (some of which portend what the character is about), and with vivid, almost poetic. description. Most of all, as a constant subtext in the writing, there is the social commentary exposing the flaws and excresences of Victorian society.
Dickens had five novels (the above two, Nicholas Nickelby, The Old Curiosity Shop, and Barnaby Rudge) under his belt when he wrote A Christmas Carol in 1843. Apparently he had quickly dashed it off for publication in order to clear a debt, and never dreamed it would be as popular as it was. As it happened it sold 6000 copies in the first week and became one of the most enduring stories about Christmas ever written. Fellow writers and critics at the time also pointed out that the story was paramount in rejuvenating the Christmas traditions and spirit, which had been in decline for a while.
The underlying themes of the story, apart from the overlaid one of Scrooge's journey towards his redemption, are the usual ones for a Dickens tale: poverty and injustice. These themes come out the most in Scrooge's dream trip with the Ghost of Christmas Present, as the latter shows him how even the poorest people in the land celebrate Christmas with a sense of togetherness. Of course, in their travels they also visit the Cratchit's who are poor beyond belief: Bob Cratchit has to support his large family on a mere 15 shillings a week working as a clerk for Scrooge. And there's his son Tiny Tim who is crippled and walks with a crutch and for whom they cannot buy enough medical care. The Ghost even warns Scrooge that Tiny Tim would die if he didn't get enough medical attention, which of course meant money.
And right at the end of Scrooge's visit from the Ghost, the Ghost shows him two emaciated wolfish children that he called Ignorance and Want, epitomizing social injustice, warning Scrooge that his very world would be rocked to its foundation if these two were not taken care of.
Dickens lived until 1870, not particularly old perhaps, but it's generally thought he never recovered from a railway crash that had happened some five years earlier. Indeed in those five years his output was small. He completed one novel already begun (Our Mutual Friend), wrote a novel in collaboration with Wilkie Collins (No Thoroughfare), and started a new serialized novel called The Mystery of Edwin Drood, which was only half finished at his death.
Ghost of Christmas Present