A topic sentence is the first sentence in a paragraph, a sentence in which you let the reader know the topic the paragraph is going to be about, the point you want to make. If you are writing just one paragraph about a book, it is best to introduce the title of the book and the author's name in the topic sentence. But you also need to let the reader know what you are going to be saying about the book. You don't want to just say, "This is a paragraph about this book by this author."
So, how you write the topic sentence is going to depend on what the main idea is that you want to share with the reader about the book. You might want to say what the theme of the book is or that one of the characters is important for some reason. You may want to say that the book taught you about some particular topic. Here are some examples of topic sentences that introduce books and authors:
Malcolm Gladwell's Blink explains a great deal about our intuitions.
"The Lottery," by Shirley Jackson, is a story about a village with a frightening and horrible ritual.
In The Great Gatsby, by F. Scott Fitzgerald, the reader sees everything that happens through the eyes of Nick, the narrator.
This is how we introduce the title, the author, and the main idea we are going to discuss in the paragraph. No matter what book or story you are going to write about, you can do this, too. Just decide what the point is that you want to make in the paragraph.