I recently listened to a summary of Influencer by Kerry Patterson. The book was alright, and I'm not sure if it was the summary or the book, but the content didn't seem as unique as I would have hoped (a lot of the same material as in other psychology/influence books I've read). That's not to say it wasn't a good introductory/summary book for the topic.
The book started with the two most basic questions people ask: Am I able? and Am I motivated? The book's goal was to demonstrate six steps to influencing people's attitudes towards those two questions.
1. Make the undesirable desirable