The present book revolves around the introduction and potential functions of endophytic fungi in the field. The book presents four important sections, including (i) the introduction of endophytic fungi, (ii) diversity and antimicrobial activity of endophytic fungi from mangrove forests, (iii) positive effects of arbuscular mycorrhizal fungi on ornamental plants, and (iv) potential application and assessment of arbuscular mycorrhizal fungi on fruit trees, vegetable crops, and ornamental crops.