Preface. Effect of molecular orientation on electron transfer and electron impact ionization (P.R. Brooks, P.W.Harland). Experimental approaches to the unimolecular dissociation of gaseous cluster ions (T. B. McMahon). New approaches to ion thermochemistry via dissociation and association (R.C. Dunbar). Alkyl cation-dihydrogen complexes, silonium and germonium cations: theoretical considerations (P.R. Schreiner et al.). Symmetry induced kinetic isotope effects in ion-molecule reactions (G.I. Gellene). Ion-molecule chemistry: the roles of intrinsic structure, solvation and counterions (J.E. Bartmess). Gas phase ion chemistry under conditions of very high pressure (W.B. Knighton, E.P. Grimsrud). Index.