In this talk I will introduce atomic-scale X-ray photon correlation spectroscopy, a synchrotron-based experimental method that allows us to follow the atoms during their movement in real time in a statistical sense, with a sensitivity to jump rates on timescales of seconds to hours [1]. I will review the theoretical concepts and discuss the relations to alternative atomically-resolved methods. Further, I will give an overview on our results in crystalline and amorphous matter, comprising metals, semiconductors and insulators.