Modern society has a higher demand for quality than it had before. Six Sigma approach is a successful manufacturing quality improvement tool. Recently, the Six Sigma approach was introduced in the software development industry. Some software companies have been trying to adapt Six Sigma for their business and development processes. But there are misconceptions about the applicability of Six Sigma in softwares. So there is a demand to debunk the misconceptions related to the applicability of Six Sigma. And to develop a generic software company quality improvement solution, based on Six Sigma approach. The book starts from Six Sigma concept identification and manufacturing investigation. After conducting interviews, a case study and several case studies reviews of Six Sigma in Software, we detail our method. We expect the result to be useful for software companies when applying Six Sigma in their company for process improvement.