Before the mid-90's, scientists' theories for planet formation were finely-tuned to explain the existence of our own Solar System. These theories were thrown into disarray when astronomers began to discover exoplanets, or planets in other solar systems. Forced to reconcile theory with observation, astronomers and planetary scientists have worked together for the past twenty years to solve the puzzles created by these thousands of exoplanets. One particularly intriguing group of newly-discovered planets were the hot Jupiters, planets the size of our Jupiter orbiting their host star every few days. This thesis details two observational campaigns that attempt to illuminate the origin and composition of hot Jupiters. Each project is powered by the NIRSPEC (Near-Infrared SPECtrometer) instrument located at Mauna Kea in Hawaii. The first project aims to determine the stellar multiplicity rate of hot Jupiter host stars. Such a metric can inform the migration histories of these planets. The second project treats a hot Jupiter and its host star as a spectroscopic binary. This treatment reveals the orbital elements and atmospheric composition of the hot Jupiter. The spectroscopic methods described in this thesis are small steps in the study of hot Jupiters and ultimately potentially habitable exoplanets
