Pain is an unpleasant sensation. It is defined by the International Association for the Study of Pain (IASP) as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage". Pain is part of the body's defence system: it triggers mental problem-solving strategies that seek to end the painful experience, and it promotes learning, making repetition of the painful situation less likely. The nociceptive system transmits signals that usually trigger the sensation of pain, it is a critical component of the body's ability to react to damaging stimuli and it is part of a rapid-warning relay instructing the central nervous system to initiate reactions for minimising injury. This book presents the latest research in the field from around the globe.