A great book is a literary work that is highly regarded for its content, style, and impact. It may be considered a classic or a timeless piece of literature that has stood the test of time due to its themes, characters, and storyline. A great book can also be one that captures the reader's attention and emotions, providing an engaging and thought-provoking experience. Ultimately, a great book is subjective and depends on individual interpretation, but it generally speaks to universal human experiences and leaves a lasting impression on its readers.