Basic Background -- Telomeres and Telomerase in Humans -- Telomere-Binding Proteins in Humans -- Regulation of Telomerase Through Transcriptional and Posttranslational Mechanisms -- Telomere Dysfunction and the DNA Damage Response -- Alternative Lengthening of Telomeres in Human Cells -- Mouse Model: Telomeres and Telomerase in Stem Cell and Cancer -- Telomeres and Telomerase in Human Cancers -- Role of Telomeres and Telomerase in Cancer -- Diagnostic Value I: Solid Tumors -- Diagnostic Value II: Hematopoietic Malignancies -- Therapeutic Targets and Drugs I: Telomerase and Telomerase Inhibitors -- Therapeutic Targets and Drugs II: G-Quadruplex and G-Quadruplex Inhibitors -- Therapeutic Targets and Drugs III: Tankyrase 1, Telomere-Binding Proteins, and Inhibitors -- Therapeutic Targets and Drugs IV: Telomerase-Specific Gene and Vector-Based Therapies for Human Cancer -- Experimental Protocols -- Protocol I: Telomerase Activity and Telomerase Expression -- Protocol II: Importance and Methods of Telomere G-Tail Length Quantification -- Protocol III: Detection of Alternative Lengthening of Telomeres. Telomeres and telomerase are the pivotal players that destine cellular senescence and immortalization. Telomere shortening due to "End-replication problem" in each cell cycle is a universal phenomenon for all eukaryotic cells with linear chromosomes. Its compensation by telomerase is also common from yeast to human. However, the length of telomeres, distribution of telomerase positive cells, and consequence of telomerase inhibition are different among species. "Telomeres and Telomerase in Cancers", edited by Keiko Hiyama, focuses on "Human" telomeres and telomerase, from basic biology and hypothesis in human normal cells and cancer cells to clinical application as diagnostic tools and therapeutic targets in anti-cancer strategy. Cutting-edge experimental protocols for their evaluation are also included. This coverage will enable medical oncologists and students as well as basic researchers to capture the up-to-date entire picture of human telomeres and telomerase in cancer.