Book.

Reading a book backwards can be a refreshing experience because the reader does not know what is about to happen. This can increase the tension and make the reader think about the events that are unfolding. 

For example, in a thriller, reading the ending first would add a new dimension to unraveling the murder mystery. In a science fiction story, reading the ending first might provide some surprising context for the time travel or technology described in the story.

Reading a book backwards can help the reader better notice how the author constructed the storyline. This can help, for example, to understand symbolism, motifs and themes used by the author.

 For example, in a novel about a war, reading the ending first might show how the war has changed the characters and the impact it has had on society. In a book of poetry, reading the end first might show how the poet developed the theme of the book.

Reading a book backwards can help the reader to interpret the book in a different way or discover new meanings. This can help, for example, to analyze a complex storyline or to discover new nuances in the characters. 

For example, in a historical story, reading the ending first might show how the events of the past led to the situation in the present. In a literary novel, reading the ending first might reveal how the author manipulated the characters in the storyline.