There are a number of books that could be considered realistic, depending on what you are looking for. For example, if you are interested in a book that realistically portrays the human experience, you might want to consider a book like 1984 by George Orwell. This book is set in a society that is controlled by a totalitarian government, and it explores the ways that this government controls and manipulates the people living in it. Other books that explore similar themes include Brave New World by Aldous Huxley and The Giver by Lois Lowry.
If you are looking for a book that realistically portrays the world around us, you might want to consider books like The Hunger Games by Suzanne Collins or Ready Player One by Ernest Cline. These books are set in worlds that are very different from our own, but they still contain elements that feel real and believable.
Finally, if you are looking for a book that realistically portrays the future, you might want to consider books like Ender's Game by Orson Scott Card or The Martian by Andy Weir. These books are set in a future where humanity faces challenges that we have never faced before, and they explore how we might respond to these challenges.