I was just reading Vossler's Jedi Manual Basic (2009 edition text) and came across a section on "Some techniques for dealing with Sith" where verbal self-defense skills are mentioned. The Gentle Art of Verbal Self-Defense by S. Elgin is recommended as a resource. It's a great book, no doubt.
This past November, as a part of my job, I took a training course called Crucial Conversations, which was very intense and overwhelming experience. I had to re-evaluate the way I talk, the way I approach, and the way I think during my interactions with other people. It is based on the book entitled Crucial Conversations: Tools for Talking When Stakes Are High by Kerry Patterson, Joseph Grenny, Ron McMillan, and Al Switzler, first published in 2002, with the second edition in 2012.
So, I would recommend this book as a second resource for learning important skills in dealing with people, especially when your emotions are high. It's not only for business workplaces, but for all aspects of one's life. In short, this is a practical book on essential skills and mastering of difficult in-person conversations.
So, I would highly recommend it.
