Telomeres are a region of repetitive DNA at the end of chromosomes, which protects the end of the chromosome from destruction. They protect chromosome ends from degradation and thus prevent chromosome end fusion. This book describes the relevance of telomeres in the human aging process and the telomere defects that play a role in the premature aging process. Dysfunctional telomeres that can promote chromosome instability, leading to DNA amplifications and terminal deletions-, cell cycle arrest and cell death, are also described. The biology and function of both telomeres and telomerase are...