Many companies want to hire qualified people who can manage their business. Sometimes, graduation certification is not enough to get a job because new graduated has not enough experience to do the job. There are many courses help to improve the experience like green belt six sigma and black belt six sigma. Those courses are the essential requirements for many companies. By writing black belt six sigma in search job, we will find many jobs touched this request. This book wrote because I find many fake websites on the internet offer courses of black belt, but they are not eligible for this type of courses. The book explained all techniques of black belt and applied most tools and strategies to improve quality. In the book, I presented all what we need to get a certification of black belt six sigma. ( Knock the door of a job by black belt six sigma)