If not through a sudden press release by SETI or the Mars rover team, our first news of possible life elsewhere in the universe will be via the observation of biosignatures in the atmosphere of a planet outside of our solar system. This extraordinary measurement is the motivation for the work of many astronomers and may be achievable in the not-too-distant future, but a confident interpretation of the data will require careful advanced preparation from astrophysicists and biophysicists alike. I will discuss my work on characterizing the atmospheres of exoplanets through the use of three-dimensional numerical modeling. I will emphasize the importance of using multiple types of measurements in order to identify the physical properties of a planet with confidence, so that we can build up a coherent picture of an exoplanet as more than just the sum of its parts. Finally, I will describe how the current state of this field will progress into an even more exciting future.