This book provides a comprehensive review of Toxocara and the disease it causes known as toxocariasis. It brings together a wide range of topics and approaches concerning this parasite of veterinary and medical importance, and provides a unique model system to explore questions in parasite biology. Toxocara is a parasitic helminth worm that continues to stimulate both public concern and scientific interest. Toxocara canis and T.cati, the most studied species, are gastrointestinal parasites of dogs and cats and their eggs can contaminate the environment, thus exposing humans and other mammals and birds to infection. This book will interest a wide range of general, veterinary and medical parasitologists as well as clinicians and those concerned with public health (including ophthalmologists, allergologists, dermatologists and respiratory medicine specialists).