Recent prosperity of structural biology is striking. Researches on the molecular structures of biomolecules as proteins have become the pivot of biology. Also for applied biology including medical science. solution of problems is left to structural biology. The word "structural biology" became to be used generally from the begining of 1990 era. and the academic journal "Nature Structural Biology" was published from 1994 in addition to "Nature" itself. Structural biology is ndt morphology of organisms, but molecular science of organisms, so that structural biology is molecular biology. Molecular genetics related to genetic phenomena preceeded in the field of molecular biology, so that structure, replication, transcription, translation of genes and thier regulation are considered as central problems in molecular biology. However, molecular biology is naturally "biology explained on molecular level" (R. T.Steiner). In molecular biology. researches of genes progressed to enable us to prepare large amount of a protein that existed in trace amount in an organism, and to alter protein structure artifitially. Although the word "structural biology" has been used recently the origin of structural biology was half century ago. To study the structure of a protein, J.D.Bernal and D. Crowfoot(Hodgkin) irradiated x-ray to the crystal of trypsin, and got a beautiful diffraction pattern in 1934. This showed that a protein molecule had a specific tertiary structure. M. Perutz started x-ray structural analysis of crystarized hemoglobin in 1937, and suceeded to clarify its molecular structure in 1959. Therefore, we may consider that the start of the structural biology was 1940 era, and M.Perutz was a pioneer of structural biology. Before these early workes on protein structure performed at Cambridge University, the Bragg father and son developed x-ray diffraction method for the structural analysis of low molecular weight compounds. It is a well known story that in such circumstances at Camblidge Watson and Crick clarified the double-stranded structure of DNA. Therefore, we may mention that the original place of structural biology is Cambridge in England. It is marvelous that the methods for analysis of primary structure of nucleic acids, either RNA or DNA, as well as proteins were developed and applied first for actual sequence determination by F. Sanger and his associates at Cambridge. On the other hand, the centre of researches on the structural analysis of protein and nucleic acid in water solution was Harvard University, where P. Doty was at work. In Harvard, there was W.Gilbert, who was another developer of the analytical method for the base sequence of DNA. Any big scientific work seems to be produced at the special place in fine environment.

Recently, not only x-ray diffraction, but also nuclear magnetic resonance(NMR), various kinds of microscope, and others are used as the experimental tools of structural biology, and a great number of research centers are located over the world. In Japan also, much efforts have been put for research in the structural biology, including development of research apparatus for it.