This fascinating book demonstrates that to be a good communicator and therefore an effective manager, a person must have five qualities in order to be viewed as totally credible–competence, character, composure, sociability, and extroversion. While some executives seem to possess all these qualities and be born with savvy communication skills, Weiner shows how anyone can find ways to make measurable improvements in how they present themselves that will enhance their credibility. 

So Smart But.... How Intelligent People Lose Credibility - and How They Can Get it Back