The formation of large single crystals of protein is essential for the crystallographic structure analysis. The techniques of crystallization have been developed especially when only small amount of protein is available. The conditions suitable for growing good crystals can be obtained by trial and error, but at the same time it is necessary to seek good conditions from the general empirical rules. The author, an X-ray crystallographer, wanted to introduce the general techniques of protein crystallization to those in the field of crystal growth for discussions. Here the nature of protein is briefly shown and the techniques of crystallization are presented. An example of crystallization of immunological proteins is also shown in some detail.
