This book compiles recent research on the modification of nucleic acids. It covers backbone modifications and conjugation of lipids, peptides and proteins to oligonucleotides and their therapeutic use. Synthesis and application in biomedicine and nanotechnology of aptamers, fluorescent and xeno nucleic acids, DNA repair and artificial DNA are discussed. New: expands on DNA nanotechnology and presents the fundamentals and new development of RNA therapeutics including CRISPR/Cas9, RNA editing and mRNA vaccines. Novel backbones for therapeutic nucleic acids. Lipid-, peptide- and protein-oligonucleotide conjugates. Modified DNA nanostructures. Aptamers and DNA catalysts. RNA therapeutics.