This book explores the intricate relationship between microorganisms and cancer. It begins by discussing the microbiome of the human body and its role in cancer development. The cellular organization of tumors is also explored in detail. The book then delves into the specific microorganisms that have been associated with various types of cancer. The role of HCV in hepatocellular carcinoma is discussed in depth, as well as cancers associated with EBV. Further, it also explores the link between HPV and urogenital and head and neck cancers, and Kaposi’s sarcoma-associated Herpes virus. The chapter is dedicated to dispelling myths surrounding Aspergillus and lung cancer and examines the complications associated with fungal infections in cancer treatment. The book then explores the link between parasites and cancer, and the role that protists play in cancer development. Finally, the book concludes with a discussion of cancer management and therapies related to microorganisms. Overall, the book provides a comprehensive overview of the relationship between microorganisms and cancer and sheds light on how this relationship can be harnessed for more effective cancer management and treatment.