ASUMMARY is given of key features of the computer program VICONOPT,1 which covers prismatic assemblies of anisotropic plates exactly for buckling and vibration analysis and also for design subject to buckling constraints. Contents VICONOPT (VIpasa with CONstraints and OPTimization) is a 23,000 line Fortran 77 computer program that incorporates the earlier programs VIPASA2 and VICON.3 It covers any prismatic assembly of anisotropic plates and Fig. 1 shows typical cross sections. Each plate can carry any combination of NL, NT9 and Ns, the longitudinally invariant in-plane forces per unit length of plate edge shown in Fig. 1. VICONOPT performs analysis or optimum design. The analysis includes calculation of critical buckling load factors, or undamped natural frequencies, and mode shapes. VIPASA uses the stiffness matrix method based on exact flat plate theory with Winkler foundations. It also uses an algorithm that guarantees convergence on all required eigenvalues and permits the user to employ nested (to any level) substructuring very concisely and flexibly to reduce solution times, data preparation, and computer memory usage. The mode of buckling or vibration is assumed to vary sinusoidally in the longitudinal direction x> with the displacement amplitudes u, v, w, and ^ shown in Fig. 1 and with computations being repeated for a user specified set of half-waveleng ths X. Plate bending and membrane behaviors are uncoupled and the bending and in-plane stiffness matrices D and A are respectively fully populated and orthotropic, which treats balanced symmetric laminates. The global stiffness matrix becomes complex when anisotropy or shear loading are present, thus, increasing solution time. The nodal lines of zero displacement are straight and in the y direction if all plates are orthotropic with Ns = 0, and so satisfy simply supported end conditions. Otherwise, solutions only approximate such end conditions and become excessively conservative as A approaches L Dead load values of NL, NT9 and Ns are permitted for both buckling and vibration problems. In the former case they are additional to live load values that are factored until buckling occurs. Plate loadings may be given as data, although NL is usually calculated from the total longitudinal load on the panel or