Divided into four sections, this work presents the proceedings of an international symposium on monitoring of gaseous pollutants by tunable diode lasers. Focusing on atmospheric trace gas detection, the presentations 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 mu-m 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 an expert discussion of a vital research area.