Though Mark Twain is best remembered as perhaps the quintessential American humor writer, he was also a keen observer and critic of cultural and social trends. In this vein, he undertook a book-length discussion and analysis of Christian Science and New Thought, both of which enjoyed immense popularity in the nineteenth and early twentieth centuries in the United States. The controversial text was originally rejected by Twain's publisher, a gesture that the author saw as confirming the influence and power of the religious movement.