Nucleoside polyphosphates and their conjugates, such as nucleoside triphosphates, nucleoside tetraphosphates, sugar nucleotides, dinucleoside pyro- and higher order polyphosphates, 2',3'-cyclic nucleoside monophosphates, and 2 -deoxynucleoside-5 -tetraphosphates in which a fluorescent label is attached to the terminal phosphate have many biological roles and have been developed into drugs. However, their synthesis remains a challenge. This book discusses several novel and efficient approaches to the synthesis of nucleoside polyphosphates and their conjugates.