2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/1820I review the optical and near-infrared spectral characteristics of the extremely cool dwarfs grouped under the new classification of type L. These include both very low-mass stars and brown dwarfs, and we discuss the likely temperature range. Finally, we consider the frequency of binaries amongst very low-mass dwarfs, and the implications for formation mechanisms.20 pages, 14 figures (2 as gif files); Review talk at Galactic Structure, Stars and the ISM Conference (Grand Teton, May, 2000). arXiv admin note: figure 11 is correct.Astrophysicstext