Book excerpt: This book is intended as a textbook for 3rd year undergraduate students, as well as postgraduate students. It comprises a review of the current opinion regarding the evolution and adaptation of terrestrial arthropods, beginning with the paleontological, embryological, morphological and physiological evidence. The implication of size is then considered in relation to life on land. A discussion of insect phylogeny and the origin of flight is followed by an account of evolutionary trends in reproduction. Further chapters cover adaptations to extreme environments, dispersal and migration, defensive mechanisms and, finally, present arguments for the success of the terrestrial arthropods in general.