The section of this handbook has been dividing into two volumes, the first volume contains information relating to purines, pyrimidine and nucleoside, oligonucleotide, polynucleotides, and their derivatives. Both ribo and deoxyribo compounds are listed also. The second volume will contain the remaining material similar to Volume 1 and material more relative to genetic and biological aspects such as enzymes involved in nucleic acid function, protein synthesis, linkage maps.