What types of things did Mark Twain generally write about?
I'd have to say it would be generally the times of his life. He
travelled to California during the gold rush and wrote about that
as well as several tall tales (Jumping Frogs of Calaveras County).
Huckleberry Finn and Tom Sawyer were based on his Mississippi River
days--he had quite a gift for dialect. He went to the middle east,
traveling across the Suez Canal from Egypt to Jerusalem (Roughing
It). A lot of his fiction was commentary--A Connecticut Yankee in
King Arthur's Court is entertaining on the surface, more serious
below. Same with Huckleberry Finn and Tom Sawyer. After his wife
and children died, he became embittered, and there are some
writings about Satan. I'm not sure about the timeline of his
writings, but he was writing in the late 1800s. There is also a
website that includes a lot of his quotations: