The major theme or themes of a book are the recurring ideas that point to important topics outside of the story. For example, in Shakespeare’s Romeo and Juliet, Shakespeare spends a lot of time on the young lovers's affection toward one another and on the two families's feud. He is pointing to themes about love, family obligation, and conflict. A helpful way to detect the theme is to note which ideas keep appearing, what the characters spend the most time talking about, or which sections of the book spend the most time on certain topics. If a character has a lengthy speech about a topic or the author takes the time to talk about a particular scene at length, that can signal a theme. Think about the opening of A Tale Of Two Cities, in which Dickens talks about the historical setting of the novel and the similarities and differences between London and Paris. It is a long introduction and does more than set the stage—it discusses larger points about political conflicts and culture.
The theme is often referred to as the “meaning” of the story, yet a story can have more than one theme or even a contradictory meaning. Think of a novel or short story that pitted two sides against each other without necessarily taking one side. A theme doesn’t always provide a clear moral. Sometimes a theme lets the reader consider two sides of one issue and make up their own mind. For example, in The Hunger Games series, author Suzanne Collins makes the reader sympathetic to Katniss Everdeen’s unwillingness to fight in the games: the reader feels the emotional toll it takes on Katniss—how much she misses her family and her own objections to the games themselves. At the same time, the reader understands the consequences if Katniss chooses not to fight for her district. The author is not making a point about which side is wrong or right but instead showing the emotional complexity behind this important decision.
Finally, another helpful way to determine the theme of a story is to highlight which sections keep standing out to you. Highlight in the text (or keep a separate list) of which parts were interesting to you or moved you emotionally. What kept making you sad, laugh, think, or even disturbed you? Then see what those sections have in common. Sometimes the theme of a story is not immediately apparent. A reader may even explore themes the author didn’t have in mind. Whether it is the author’s theme or the reader’s interpretation, it is important to always find sections of the text to back up your points. Always refer to the story, and whenever possible, refer to specific lines or words in the text.
The theme of a novel is implied. This means it is not usually directly stated in a short story or a novel.
You read the book and you realize something. It is "the author's message" to you. You can watch and see how the main character learns something and changes. If you look closely, at how the main character changes you will often see the "theme" of a novel emerge.
The plot of a novel refers to the action of the novel. It is "who does what to whom". It is what happens in a story. it is very different from the author's message or the theme.
The theme is much more about "why" a character is transformed or changed.