A lot of times, when you're at a book signing, you're asked to read a section of your book aloud. Readers are more likely to buy a book if they can meet the author. They're even more likely to buy it if they can hear the author read or speak. It personalizes the book. Just as an autograph makes the book memorable, so does a reading.
It's important you keep in mind, though, that you should be doing more than reading your book. You should be interpreting it.
My specialization when I got my Masters degree in Speech Communication was Oral Interpretation. That meant taking the words someone else had written and orally interpreting them for an audience. In a great sense, it's like acting. You memorize the passage then bring it alive -- through your voice, primarily. You'll put some facial expression into it, maybe even a gesture or two when appropriate. But you won't be expected to walk here and there or act out the scene.
As the author at a reading, you won't have to go that far. First of all, you're reading your own words, not someone else's. Secondly, you don't have to memorize it. Of course, you wrote it; you edited it a trillion times. You have it practically memorized already. This is good. When you're reading, you want to be looking out into the eyes of your audience more than you're looking down at the book.
But you don't want to do a flat reading. Even if what you're reading is an exciting part of the book, if you read it in a monotone, you'll lose your audience or put them to sleep.
Tomorrow: How to Prepare for a Reading
2 months ago