In this pocket-sized handbook we have attempted to meet the need for condensed and readily accessible information about viruses as agents of human disease. We hope that this book will provide useful information for all healthcare professionals, in particular practising physicians, medical and nursing students, interns and residents. We have included some new chapters on hepatitis and herpes viruses to this new edition, whereas the arboviruses chapter has been taken out. The cartoons will hopefully entertain as well as provide a helpful visual image of some salient points. The gestation period for this new edition was very long. Hopefully the offspring will please.