A book series is a collection of related books that share common characters, settings, or themes. Each book in the series typically follows a sequential order, allowing readers to experience a continuous storyline or character development. Popular examples of book series include Harry Potter by J.K. Rowling and The Chronicles of Narnia by C.S. Lewis. Readers often enjoy book series because they can immerse themselves in a larger narrative over multiple volumes. This format allows authors to explore complex plots and character arcs in greater depth. Additionally, fans of a series may look forward to new installments, creating a sense of anticipation and community among readers.