This book represents a renewed effort of the continuous attempts on the road to fight the well known pest cotton leaf worm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) in Egypt and minimize the damage of this destructive insect, which cause a lot of severe losses in various crops and plants especially cotton plantations, resulted in excessive use of chemical control agents leading to several environmental and human health problems. Current book includes many tests performed under laboratory and field conditions to study the efficiency of some compounds used in control this defoliator at various stages, the response of larvae to different tested enzymes as well as side effects against some associated predators in cotton fields, such knowledge may help in the reasonable control strategies of S. littoralis.