Gas Chromatography (GC) is a commonly used analytic technique in many research and industrial laboratories for quality control as well as identification and quantitation of compounds in a mixture. GC is also a frequently used technique in many environmental and forensic laboratories because it allows for the detection of very small quantities. A broad variety of samples can be analysed as long as the compounds are sufficiently thermally stable and reasonably volatile. Like for all other chromatographic techniques, a mobile and a stationary phase are required for this technique. The mobile phase (or "moving phase") is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen. Helium remains the most commonly used carrier gas in about 90% of instruments although hydrogen is preferred for improved separations. The stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside a piece of glass or metal tubing called a column. The instrument used to perform gas chromatography is called a gas chromatograph. Gas chromatography is also similar to fractional distillation, since both processes separate the components of a mixture primarily based on boiling point differences. However, fractional distillation is typically used to separate components of a mixture on a large scale, whereas GC can be used on a much smaller scale. This book explores the essential aspects and details of certain gas chromatography applications in plant science, wine technology, toxicology and the other specific disciplines that are presently being researched. It provides a contemporary picture of the field, including fundamentals and practical applications, in a single source.