2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/14374Determinations of the main cosmological parameters are reviewed and the implications for cold dark matter discussed. There is no longer an age problem for an $Ω_o = 1, Λ= 0$ model and, if anything, there is now an age problem for low $Ω_o, Λ> 0$ models. Large scale structure and CMB fluctuation data are best fitted by a mixed dark matter $Ω_o$ = 1 universe. Difficulties for this model with cluster evolution, the baryon content of clusters, high z Lyman $α$ galaxies, and the evidence from Type Ia supernovae favouring low $Ω_o, Λ> 0$ models, are discussed critically.13 pages, 3 tables, to appear in Proceedings of the 2nd International Workshop on 'The Identification of Dark Matter' (IDM'98), Buxton, UK, 1999, ed. N.Spooner, (World Scientific)Astrophysicstext