Nematodes are well known for their ability to survive environmental extremes. Their survival mechanisms for cold tolerance, thermobiotic, osmotic and ionic stress mechanisms are presented here together with information on the underlying biochemical basis contributing to survival. Highlighting parallels and contrasts between groups, the book integrates information on the strategies that enable nematodes to overcome a lack of food with tactics used by parasitic forms to survive the defence responses of a plant or animal host, or the absence of a host.