The aim of this book is to describe the current knowledge about the welfare of laboratory animals. There is previous literature dealing with the welfare of animals in general, as well as literature dealing with the maintenance and use of laboratory animals. This book brings together these two topics, focusing on the general and species-specific needs of laboratory animals in the light of their welfare. The book will provide material for researchers, lecturers, students and technical staff working with laboratory animals. The authors of this book are leading European scientists in laboratory animal science.