2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/11215We present a review of the most recent improvements in the theory of low-mass star-like objects, in the stellar and sub-stellar domains. Comparison is made with various recent observations.10 pages, Latex file, uses crckapb.sty, Review talk : IAU Symposium 189, Fundamental stellar properties: the interaction between theory and observation, Ed. T.R. Bedding, A.J. Booth and J. Davis (Kluwer; Dordrecht)Astrophysicstext