There is merit to either purpose; it's not a case of one or the other.
Books that portray the world as it is are called factual texts. We learn information from them that can help us to understand, relate to, and change the world.
Books that portray the world as it should be may be called fiction, may be called inspirational, could move into the area of science fiction. They may give us food for thought about how things might be - and perhaps should be - changed.
Books could also portray worlds that are completely fictional and totally unrelated to any current experience. These may be called escapism, but can also be called great fun!
Books should clearly do both. In addition, they should also portray the world as it should not be. Different books can make their points in each of these ways.
For example, you can have dystopian novels like 1984 that show us neither what the world is like nor what it should be like. However, by looking at what it should not be like, we learn about what it should be.
In other books, like The Jungle, we learn about how the world is. This can allow us to see the world's problems and be inspired to fix them. Finally, you have books like Utopia or Looking Backward that tell us about an ideal world.
All of these kinds of books can tell us important things about what the world should be like.
This is a tough one. Any answer is going to be challenged with "the other." To make matters worse, there is nothing really definitive out there because the question is so challenging. Essentially, what you are asking is what is the role of the artist. The best that can be done here is to outline the arguments and allow you to really think about where things stand in your own mind and progress from there.
I am going to pull "the fencesitter" position here and permute both points of view, though. I would strongly consider that you examine the movement of social realism that was very big in American Literature of the 1930s. Given the Great Depression and the economic challenges that gripped America of the time, artists felt ethically and professsionally obligated to depict the reality of the world as it was. From this, they believed that individuals could possess the capacity to envision the world as it should be. Social realism could be the one domain that ends up combining both of the challenging polarities of your question. For example, the photographer Dorothea Lange takes pictures of real life in the 1930s, of people enduring economic hardship. Examine her portrait entitled Migrant Mother as an example of this. She does this to show how the world is so that the consciousness of both individuals and society are awoken to how the world should be as opposed to how it is. John Steinbeck is another great example of this. In works like The Grapes of Wrath and Of Mice and Men, he shows how the world is in an unflinchingly brutal manner. Steinbeck pulls no punches in this process. Yet, he shows how the world is so that individuals reading his works can understand how there is a pressing need to transform it into how it should be. In social realism, the artists depicts the world as it is in order to facilitate social change to what the world should be. It is here where both sides of the question can find a home into one.
books are the souce of inspiration , guidance , knowledge and food for thought . they should cater to both of the need of human beings viz entertainment as well as education. only the entertainment books and news magazines present the the world as it is and what is going on in this world but most of the books of lierature presents both the thing s or views ie how the world is now and how it should be. actually the literatti is concerned about the silent revolution which can only be brought about through the written or spoken world sometimes they use the strokes of brush to to take us to a cruise from the past to future. A happy and peaceful world has ever been a DREAM OF THE WRITERS FROM THE ADVENT OF HUMAN BEINGS AND THEY ALWAYS STRIVED FOR IT BY PRESENTING A COMPARISON OF THE PRESENT WORLD WITH THE WORLD TO BE .
books should never portray a single world as it is going on it should always present both the things how it is nowadays and how it should be as it has an inspirational role to play so if it presents a world of today in which therir is violence and sex freaks it would ruin the young minds , it should present the world also inwhich we can get rid of these things.
Books can do both, portray the world as it is, or portray a desired world. But they don't necessarily have to do both. They may very well do just the one or the other.
Books that portray the world as it is are called Realistic Fiction or Literature. Examples are Emile Zola, Honore de Balzac, etc.
Books trying to present an ideal world are called either Escapist or Utopian Literature. Examples are "Looking Backward"by Edward Bellamy, "Erewhon" by Samuel Butler, "Utopia" by Thomas More, etc.
There's room for both; there's actually a need for both.