This document is intended to provide the newcomer to headspace sampling with a concise summary of the theory and principles of this exciting technique. Enough information is included here for the user to understand the basic concepts and relationships in HS sampling to apply during method development and interpretation of data. Although emphasis is given to the PerkinElmer TurboMatrix™ HS systems, the document also covers alternative systems so that it should be useful to all potential users of HS systems. It is not intended to be a comprehensive review of the subject and the reader is directed to an excellent book on this subject by Bruno Kolb and Leslie S. Ettre entitled “Static Headspace-Gas Chromatography”. This book is available for purchase from PerkinElmer under the part number: N101-1210.