Mark Twain, O'Henry, and Calvino are considered one of the three great masters of modern fiction. Their works were loved by readers and widely spread. Mark Twain's novels were mainly humorous and satirical, often describing the lives of some people at the bottom of society. His works have strong American characteristics, including slang, spoken language and humorous elements. He also created many famous characters such as Tom and Jesse sawyer. O 'Henry's novels were usually set in the background of a wealthy businessman or lawyer. He revealed the dark side of society and the complexity of human nature in the form of short stories. His works were dramatic and the uncertainty of the ending made it difficult for the readers to predict the development of the story. O 'Henry and Mark Twain's works both had their own unique styles and characteristics, but their subject matter and form were slightly different. In contrast, O 'Henry's works were more humorous and relaxed, while Mark Twain's works were more serious and in-depth. Although Mark Twain and O 'Henry were both great, their works had different styles and subjects, each representing different eras and cultures.