We summarize a research program on remote optical measurements of humidity and temperature and give new results of such measurements as well as new data on the near IR absorption spectrum of H20. The basic atmospheric technique is differential absorption lidar (DIAL) using narrow band, tunable dye lasers. Approximate wavelengths are 720, 820, and 940 nm (H20) and 690 and 760 nm (02; temperature). The requisite absorption line strengths and widths are measured in a controlled environment by means of grating spectroscopy and tunable lasers. Prospects for routine lidar meteorology, even from airplane and satellite platforms, appear excellent. In several important applications, the conditions and the optical properties of the atmosphere can be obtained remotely by these means.