In “Becoming Dickens,’’ author Robert Douglas-Fairhurst charts the writer’s rise from debtor’s son to London literary sensation, and shows how the rapid cultural, economic, and technological changes of the time enabled his transformation. He also muses on the uncomfortably large role that chance plays in success, postulating that mere circumstance could have easily doomed Dickens to a life as a clerk or journalist, thus depriving the world of a great artist.