Telomere is the nucleoprotein complex located at the endmost chromosomal terminus and one of the essential cis-acting structural elements of chromosomes. Telomeres are composed of DNA, proteins, and RNA. In this book, the authors present current research in the study of the biological functions, sequencing and ageing of telomeres. Topics discussed include the biology of telomeres in multipotential stromal cells; telomere maintenance in the blight fungus ustilago maydis; telomere length in lymphoid malignancies; unravelling the genetic basis of the alternative lengthening of telomeres and the adjustment of telomeres by cell-matrix interaction.