Biofuels provide an environment friendly alternative to world energy problems and they can be produced with the help of cellulase. Cellulases are enzymes which can help in efficient utilization of cellulose containing waste and results in useful byproducts production. I have planned this work to provide help to all those which are currently involved in cellulases research. Detailed experiments were conducted to provide deep insight into cellulase enzyme production, characterization and its optimization. Chapter 1 provides a detail introduction about cellulases production, types, sources, industrial importance etc. Chapter 2 and 3 gives a detail about chemicals and experiments which can be used for cellulase extraction and optimization to get maximum products. I hope this book will be useful for those which are new in cellulase field as well as for those which are already working on it.