This contributed volume provides an in-depth examination of entomopathogenic fungi, focusing on their diversity, ecological roles, and potential as biocontrol agents. It brings together contributions from leading scholars and practitioners to explore key research and applications in this dynamic field. The chapters cover a wide range of topics, including classification and evolutionary dynamics of entomopathogenic fungi, their genomic and molecular determinants, and their interactions with insect hosts. The book also explores the role of secondary metabolites in fungal virulence, along with innovative applications in agriculture and pest management. Additionally, it addresses the challenges and opportunities in commercializing these fungi for sustainable agriculture, providing a comprehensive overview of their biocontrol potential. Further, it discusses the diverse applications of fungal secondary metabolites in the pharmaceutical industry and medicinal chemistry. Blending theoretical perspectives with practical case studies, this volume serves as an invaluable resource for researchers, students, and professionals in mycology, entomology, and biotechnology. Readers will gain a deeper understanding of the ecological roles of entomopathogenic fungi and their transformative potential in pest management and sustainable agriculture.