Comprehensive two-dimensional gas chromatography (GC × GC) was introduced about a decade ago and is, today, rapidly becoming a powerful and widely applicable technique for the characterisation and analysis of a variety of complex samples. GC × GC provides structurally ordered chromatograms in the 2D plane, and features an impressive peak capacity. Combining GC × GC and time-of-flight mass spectrometry (ToFMS), with its fast acquisition rates and excellent deconvolution potential, has been an important step forward which enables identification and identity confirmation of large numbers of target analytes and unknowns in one run. Up until now, some 150 papers have been published in this area. Many of these deal with applications in fields such as petrochemical, fish and food, environmental and air analysis. Polyhalogenated aromatics and other priority pollutants, flavours and fragrances, fatty acid methyl esters and essential oils, are among the classes of compounds which frequently receive attention. In summary, GC × GC is increasingly being recognised as the separation technique of choice in problem areas.