There are a number of chemical vapor sensing technologies utilizing electrical, optical, mechanical and gravimetric principles. The sensing platforms in these are typically some kind of solid-state devices hooked up with microelectronic circuits for signal read-out and data acquisition [36,37]. Most important solid-state vapor sensor types are: metal-oxide semiconductor (MOS) and composite conducting polymers (CCP) chemiresistors, micro- and nano-cantilevers, bulk acoustic wave (BAW) resonators [commonly known as QCM (quartz crystal microbalance)] and surface acoustic wave (SAW) oscillators [38–43]. These sensors are fast, sensitive and reversible, and their fabrication methods are compatible with standard integrated circuit technology. The latter aspect makes them suitable for volume production, hence for cost reduction. Most of other components associated with fluidics, signal handling and data acquisition aspects of the electronic noses are either commercially available, or can be manufactured through established commercial procedures [36].