Whether it is a short story, a whole book, a sales presentation, or a pitch for a movie concept, the main idea is very important because it basically explains or gives the overall impression of the material. All other details involved in a particular story, for example, may also be important, but these only function to support the basic and main idea. Without the main idea, a particular story or book would not feel complete.
In the case of children’s storybooks, for example, there may be many characters and situations involved. There may be one or two main characters of the story that journey through a particular situation in life. These characters may be represented by animated people or animals which are going through different situations. The story may be presented using colorful drawings and animated characters to stimulate the wild imagination of children, but these visual representations may only serve as accessories or support to the story’s main idea which may be in the form of a moral lesson. A bunch of little puppies may be depicted as having to share food prepared by their mother, and the actual main idea is to convey to children readers that sharing is good for the family. Without this main idea of sharing, the story will just be interpreted as something about dogs and puppies and not much about any important message.
With the main idea, the author of a particular material is able to convey to readers what he/she really means or intends to imply. By knowing the main idea, one will better understand the material or story without actually having to go through all the supporting details. In the case of reading, the main idea may be presented in a plot summary for readers to have an initial understanding of the whole book, for example. Without reading the whole book and by having the main idea of the story, readers will be able to decide if they would go on to read the entire book.