A number of sessions will be organized around special topics as follows: (Comm. 1) Measurement on and Related to Antennas Operating between 10 and 100 GHz, RF Techniques for Measurement of Pollution of Air and Water; (Comm. 2) Propagation Measurements with ATS5, Remote Sensing of Surfaces, Remote Sensing of Atmospheres; (Comm. 3) Ionospheric Perturbation; (Comm. 3 and 4) Conjugate Effects in the Ionosphere and Magnetosphere; (Comm. 4) Magnetospheric Perturbation; (Comm. 5) Spectral Line Interferometry, Long-baseline Interferometry; (Comm. 6) Time Harmonic and Transient Radiation and Diffraction, Stochastic and Nonlinear Effects, Adaptive Arrays, Beams and Open Resonators.