This book includes taxonomical, physiological, biochemical and molecular studies of amylolytic thermophilic actinomycetes. A total of 36 actinomycetes were isolated from soil, mushroom compost and other compost samples. Four of the isolated thermophilic actinomycetes that exhibited the highest amylolytic activities were characterized and identified as: Thermoactinomyces sp, T. vulgaris and T. intermedius (two isolates). T. vulgaris, the best producer of ?-amylase, was selected for further investigation. The optimum conditions for the production are: 24 hours incubation, 55§C, pH 7.0, starch and tryptone as carbon and nitrogen sources, respectively. At different conditions of production, ?-amylase electrophoresis profile had the same pattern of two isozyme with molecular weight between 135 and 145 kDa. Purification of this ?-amylase was carried out by ammonium sulfate precipitation, dialysis, gel filtration and anion exchange chromatography. Physiochemical and molecular studies of the crude and purified enzyme revealed a novel thermostable, high molecular weight, calcium independent with wide pH range alpha-amylase. This enzyme could be of importance for industrial applications.