Monitoring of Gaseous Pollutants by Tunable Diode Lasers is divided into four sections: I -- Atmospheric Trace Gas Detection; II -- Diode Lasers and Their Properties, including Progress in IV-VI Physics and Optoelectronic Devices; III -- Techniques, Systems, Components; IV - Special Applications. Atmospheric trace gas detection was of central interest, and the presentations clearly demonstrate the impressive capabilities of the diode laser technique. Reports on IV-VI mid-infrared diode lasers stress those properties -- radiation noise and emission linewidth -- which are essential for application to ultra-high sensitivity pollution monitoring. Two reports on III-V systems emitting at wavelengths shorter than 3 mum show that the less severe cooling requirements can lead to more compact equipment which can be used to detect pollutants via overtone absorption bands. The presentations on IV-VI physics and devices stress the physical and technological aspects of mid-infrared diode lasers. Laterally structured diode lasers are discussed in detail. There is also extensive material which compares traditional AM and the more recent FM techniques. The reports on special applications point to new directions for research, thus rounding off a complete, expert discussion of a vital research area.