The aim of this book is to introduce a new technique for measuring particulate concentration in hydrocarbon air flames. The proposed technique termed SCED (Soot Concentration Estimate via Deposition) determines soot concentration by measuring the thickness of soot driven by thermophoretic effects which deposit on a tungsten wire. Soot formation process and soot effects are also outlined. Based on experimental results which are discussed in this book, SCED appears to be a valid technique.