There are already several textbooks of Gas Chromatography that treat the subject in considerably less space than our comprehensive text. Moreover, most of them include a great deal of introductory theory, which we omitted from our larger book because of space considerations. The net result is that the book contain real content of Gas Chromatography. The purpose of Gas Chromatography, is to meet the needs of teachers who present this subject to students who do not have the time or perhaps the inclination to pursue it in depth, but who may also require explicit coverage of basic topics. We therefore introduce material of this type, in an elementary fashion, and present only the main facts.