This publication contains the proceedings of the 42nd Congress of the International Society for Applied Ethology. A total of 251 contributions were presented during the congress. The current food crisis is among many challenges facing agriculture in the world today. It is fitting then that the theme of this book is 'Applied ethology: addressing future challenges in animal agriculture'. The basis for this theme is that knowledge and understanding of the principles and processes that govern farm animal behaviour can be transformed into practices that provide sustainable solutions to the challenges currently facing farm animal production systems. This book reflects the theme but also demonstrates the diversity of research in Applied Ethology.