Six Sigma methodology is a process performance level measures products defects and a statistical tool to evaluate process capability. This book is an introduction to Lean six sigma methodology and focus on Yellow belt part. It contains: Modules 1: What is six sigma and why it is needed? Module 2: What is Lean manufacturing? Module 3: Six Sigma project steps DMAIC Module 4: Apply Six Sigma in the company LEAN SIX SIGMA can be implemented in any sector or division in manufacturing or services ,in simple words, it aims to decreases losses or wastes to increase profit using statistical methods to proof results. This book is a good guide to start learning about six sigma and lean manufacturing. From students to professionals or any interested person in improving processes and continuous improvement in any sector can benefit from this guide and introduction. From my experience as a green belt certified professional, i found six sigma is a good methodology to improve companies processes and increase profit. I did this book to enhance and encourage others to learn about it, implement it and reduce wastes in all domains in manufacturing and services.