Deoxyribonucleic acid (DNA) is a chemical found primarily in the nucleus of cells. DNA is a long, spiralling molecule that orchestrates the cell's daily operations and provides the genetic blueprint for the physical characteristics of all living organisms. It is the molecule that encodes genetic information in the nucleus of cells. It determines the structure, function and behaviour of the cell. DNA is made up of two complementary strands, the strands intertwine like a spiral staircase to form a structure called a double helix. Subunits, called bases, are the rungs of the staircase. The four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine (C), and thymine (T). This book presents leading-edge research in this dynamic field.