The combination of panoramic imaging surveys plus highly multiplexed spectroscopic surveys is transforming our understanding of how the Milky Way discs evolved and are evolving. There is increased appreciation of the importance of internal processes, driven by gravitational perturbations, in determining the structure of the thin disc in particular. I will present new results concerning both thesmall-scale and large-scale structure of the Milky Way discs, and the implications for the relative importance of internal and external effects.