Plant mycobiome represents a diverse array of plant associated communities of endophytic and epiphytic fungi These communities fundamentally affect plant health development adaptation and communication with the surrounding ecosystem Furthermore they have key roles in the establishment diversification productivity and sustainability of different natural ecosystems However some of these communities are pathogenic for the plant itself or dangerous for the consumers due to the production of mycotoxins In other words plant mycobiome represents two faces of a coin This book aimed to explore contributions of the plant mycobiome in plant environment interactions from different perspectives Chapters of this book address numerous themes covering the recent advances in roles diversity and dynamics of these fungi as biocontrol agents biofertilizers growth promoters and their secondary metabolites in the area of crop improvement for sustainability and biotechnology as well as the plant pathogenic and toxigenic fungi This book will be useful to postgraduate students botanists mycologists ecologists plant pathologists and physiologists