In less than two decades, the field of exoplanetary science has undergone nothing short of a revolution. Since their discovery, planets have been found around every type of star, and current statistical estimates indicate that, on average, every star in the Milky Way hosts at least one planetary companion, which means approximately 10^11 planets. The Gaia mission itself will discover tens of thousands new planets. With such wealth of systems discovered, the next step in exoplanet research is to characterise the properties of these systems in order to understand their nature, their formation and evolutionary history. One way of doing so is by measuring the chemical and thermal parameters of their atmospheres. In this seminar will give an overview of what we know about these foreign worlds, the current techniques used and discuss the strengths and pitfalls of exoplanetary observations.