This book provides a comprehensive and current perspective on cancer research. It covers cancer biology through seven well-laid-out sections. Section I describes normal cell division, cellular homeostasis, and malignant cell transformation. Genetics, cancer epigenetics, cell cycle checkpoint, and growth-regulatory gene expression are covered in Section II. Section III discusses carcinogens, which cause cancer. Section IV describes molecular changes in cancer genes and signaling pathways, which are also employed to develop precise cancer diagnostics and treatments. Section V discusses tumor initiation, progression, metastasis, and therapeutic response, which depend on tumor cell–microenvironment interactions and their impact on disease. Section VI covers cancer diagnosis and newer, more targeted treatment. The post-genomic age and molecular methods have boosted cancer research. Section VII shows how molecular profiling, proteomics, metabolomics, and system biology might help comprehend this complicated disease. This section also discusses the microbiome's role in cancer progression and therapeutic possibilities.