Valenti's research typically involves spectroscopy of stars, but touches on many domains. He studies the structure and composition of stellar atmospheres, including the influence of magnetic fields on observed spectra. He studies stars of all ages, but is particularly interested in very young stars that are emerging from dense molecular clouds. JWST will peer into these clouds providing new insight at this early phase in the life of a star. Valenti studies stars at all temperatures, but is particularly interested in the coolest stars and brown dwarfs. JWST will obtain complete spectra of brown dwarfs at infrared wavelengths, where these very cool objects emit essentially all of their energy. Valenti studies stars that host exoplanets, particularly when the planet transits the star and is eclipsed by the star. JWST will revolutionize the study of transiting planets, obtaining detailed spectra of exoplanet atmospheres over a broad wavelength range.