The Seven Principles of Negotiations on the Edge. As a police officer, drug enforcement agent and trainer for negotiation techniques at the training institute of the Ministry of the Interior, I was confronted with the most difficult of negotiations. I negotiated mainly with kidnappers, bank robbers and drug dealers. After my studies I decided to make my experiences of the most difficult negotiations accessible to managers. In this book I recount my personal negotiation results for the first time and give you tips on how to master your difficult negotiations. Negotiations always follow the same principles, no matter if you negotiate with your partner or with difficult customers.