Influence of Tides on Species Concentrations. Preface (G.G. Shepherd). The photochemistry of the MLT oxygen airglow emissions and the expected influences of tidal perturbations (I.C. McDade). Empirical semidiurnal migrating tide model for the upper mesosphere/lower thermosphere (Yu.I. Portnyagin, T.V. Solovjova). Seasonal and local time variations in the O( 1 S) green line, O 2 atmospheric band, and OH meinel band emissions as measured by the high resolution doppler imager (W.R. Skinner et al. ). Seasonal variations of temperature near the mesopause from Fabry-Perot interferometer observations of OH meinel emissions (G.H. Choi et al. ). Horizontal parameters of the internal gravity waves registered over Yakutia (P.P. Ammosov, G.A. Gavrilyeva). E- and D-Region Physics and Modelling. Preface (W. Singer). Model calculations of the silicon and magnesium chemistry in the mesosphere and lower thermosphere (J. Fritzenwallner, E. Kopp). GLO observations of E- and F-region metal atoms and ions (J.A. Gardner et al. ). The global 3D-calculation of the distribution of the plasma components within the 80 to 130 km height range (G. Sonnemann et al. ). Comparison between an empirical and a theoretical model of the D -region (M. Friedrich, K.M. Torkar). Ion-acoustic instability caused by neutral wind action on sporadic E-layers (C.-V. Meister et al. ).