Pace and Kyeli, the authors of the Usual Error, live in Austin, Texas and their book has a good, down-home feel about it! Their style is conversational as their goal is to make understandable what is often convoluted and confounded! Each chapter is grounded with stories that illustrate two sides of a situation and/or conversation. They speak to many of the touch points of healthy communication.
While the tips and techniques offered can be applied in both personal and professional settings, I think the book will be most useful to folks looking for clarity in their personal relationships. The book does not delve into the messier aspects of how to handle conflict and behavior that is difficult.
As a primer, though, this is a warm and engaging place to start learning how to avoid all too common communication missteps that have their origin in the "usual error," i.e. thinking that others are just like me!