Fluorescence lidar is an active remote sensing technique for monitoring minor species in the atmosphere. It is based on detection of the fluorescence of atoms and molecules excited with a resonantly tuned probe laser. Rapid quenching of excited states and the associated fluorescence at tropospheric pressures limits the extensive use of fluorescence lidar to the stratosphere and above. Species which can be studied are those which can be excited to fluoresce in the .2µ to 1u, spectral region. Several years of study of Na and K in the mesosphere using ground-based lidar have demonstrated the usefulness of the technique. Detailed calculations of OH lidar proposals for the stratosphere demonstrate its usefulness for measurements of concentrations, temperatures and total pressure. Calculations of NO2 lidar proposals show that its detection is feasible, especially at night with limited range. Some species such as atomic oxygen seem to require novel approaches such as multiphoton excitation to surmount the problems of self-absorption. Experiments currently underway indicate that fluorescence lidar is about to be a major tool in the study of stratospheric composition.