This document summarizes and compares several continuous improvement methodologies: Six Sigma (6S), Lean, Theory of Constraints (TOC), TRIZ, and Shainin's Roadmap. It outlines the key principles and processes for each methodology. Six Sigma focuses on reducing variation and improving quality. Lean emphasizes removing waste and speeding processes. TOC's goal is to manage constraints to maximize throughput. TRIZ aims to foster innovative solutions through creativity. Shainin's Roadmap uses a "Red X" approach to find and address root causes of problems.