My research focuses on the properties of the lowest mass stars and coldest brown dwarfs, particularly L dwarfs and T dwarfs and ultracool halo subdwarfs. I use observational techniques to infer the physical properties of cool stars, examine magnetic activity trends, search for multiples, and measure population statistics. My work incorporates many observational tools, including optical and infrared spectroscopy, high resolution imaging (including traditional and laser guide star adaptive optics), radio astronomy, space-based (HST & Spitzer) imaging, and photometric monitoring.