The phenomenon known as Leao's spreading depression isinvestigated in this collection of ten original articles.New ideas about the fundamental mechanisms, which focus onthe involvement of polyunsaturated fatty acids and freeradicals, are presented. The relationship of spreadingdepression with clinical entities such as migraine,epilepsy, ischemic and protein-deficiency conditions of thenervous tissue are discussed as well. Studies dealing withthe application of non-invasive techniques to monitor thedisease are included.