Planetary materials provide fundamental insights into the composition and formation of the Solar System. Meteorites and their components preserve a record of the physicochemical conditions in the protoplanetary disk as well as of the evolution of planetary surfaces and interiors. Beyond the Moon, spacecraft missions have returned samples of the Solar wind (Genesis) and an S-type silcaceous asteroid (Hayabusa), as well as two C-type carbonaceous asteroids (Hayabusa2 and OSIRIS-REx) and the coma of a comet (Stardust) which sampled the outer Solar System. This chapter describes the chemical diversity of meteorites and mission returned samples and how their compositions have led to major advancements in understanding Solar System formation, planet accretion, and the building blocks of the only known life-bearing planet, Earth.