For years, toxoplasmosis has been known as disease mostly affecting newborns. Since immunocompromised patients (AIDS) present a high risk of reactivation of chronic toxoplasmosis this parasitic disease has gained increasing interest. Besides presenting clinical and therapeutical concepts, this volume provides current knowledge about genetics and immunology of T. gondii and the interaction with its 'host'. Since in vivo and in vitro models of toxoplasmosis exist, and genetic manipulation has become possible, this protozoan parasite has recently been accepted as a model for understanding the pathogenesis and persistance of other intracellular parasites. The articles of the book compromise both reviewing current concepts and reporting on yet unpublished results of leading scientists in this field.