Chemical detection techniques for explosive and illicit drug identification were originally directed towards the detection of vapors, with research groups aiming toward the specific target of creating a mechanical dog. With the advent of the mass spectrometry based contraband detection systems, exemplified by the CONDORTM which relies on both the detection of vapors and particles, research groups and instrument manufacturers changed direction and began to develop techniques mainly oriented toward the detection of trace particles. The major advantage to the use of trace particulate residues in the detection of hazardous material is that the actual substance can be identified in nearly all cases. On the other hand, as is discussed in detail in later sections of this document, sampling of complex items can be difficult. Both vapor and particulate sampling can be invaluable in the detection of hazardous materials. In many instances the techniques offer complementary information, and results obtained via one route may lead to the use of the alternative method (for example, the vapor detection of taggants as a screening technique followed by particulate analysis for the actual target). The concepts discussed in the remainder of this paper focus on the use of tandem mass spectrometry as an analytical device in the detection of contraband materials.