This new textbook provides a comprehensive introduction to all aspect of plant diseases, including pathogens, plant-pathogen interactions, their management, and future perspectives. Plant diseases have limited crop production for as long as humans have engaged in agriculture and horticulture. With climate change, globalisation and increasing awareness of the impact of pesticide use on the environment, today there is increased focus on food security as well as the various impacts of productive agriculture. Written by a group of Nordic professors and teachers of plant pathology who have collaborated together for many years, the book gives expert and seamless coverage. Their approach to plant pathology is to describe the nature of the problem, the mechanisms behind it, the kinds of organisms which cause disease, the fundamental biology of plant-microbe interactions and the approaches used to control and manage disease. The book is relevant for a worldwide audience, but offers a North European perspective in its selection of examples of plant disease.