Plants possess a rather complex and efficient immune system. During their evolutionary history, plants have developed various defense strategies in order to recognize and distinguishing between self and non-self, and face pathogens and animal pests. Accordingly, to study the plant innate immunity represents a new frontier in the plant pathology and crop protection fields. This book is structured in 6 sections. The first part introduces some basic and general aspects of the plant innate immunity and crop protection. Sections 2-5 focus on fungal and oomycete diseases (section 2), bacterial and phytoplasma diseases (section 3), virus diseases (section 4), and insect pests (section 5), with a number of case studies and plant-pathogen/pest interactions. The last section deals with plant disease detection and control. The book aims to highlight new trends in these relevant areas of plant sciences, providing a global perspective that is useful for future and innovative ideas.