Reduction of PM emission from internal combustion engine is a long term technology target for automobile engineers. Fundamental knowledge of soot formation physics, PM measurement devices, gasoline and diesel engine PM, aftertreatment system, and catalyst is needed to solve the engine PM problem. Here, purification progresses of IC engine PM are reviewed. This review book edited into 17 chapters. Former half is soot formation physics and engine emission PM. The latter half is aftertreatment and catalyst. The progresses of these technologies during 2003-2019 are mainly introduced. There are many conceptual proposals during last 20 years for the reduction of engine PM. Some of them has strong impacts on the future development of engine. Detailed explanation with many figures and tables in the book provides these concepts with historical backgrounds.