Within less than two decades, the study of low-mass stars and brown dwarfs has bloomedinto one of the most active fields in astronomy. The M, L, T and Y dwarfs sequencesincludes objects spawning more than an order of magnitude in absolute temperature, from4000 K down to room temperature, and nearly fills the entire temperature gap between thecoolest stars and our Solar System’s giant planets. I present an overview of thelarge-scale surveys that led to the discovery of a population of ultracool dwarfs in ourimmediate galactic vicinity, their classification and various noteworthy spectroscopicfeatures found only in these objects. I provide an outline of photometric variabilitystudy of L and T dwarfs, which opens a unique window on the atmospheric phenomenon at playin their atmospheres. Finally, I summarize the capabilities of an upcoming instrument, theSPIRou near-infrared, high-resolution spectropolarimeter, that will be available to theCFHT communities in 2015. SPIRou will be a unique tool for the study of cool dwarfs, andwill be used to undertake an ambitious survey of habitable Earth-sized planets aroundnearby M dwarfs.