This talk serves as an introduction to the Nordita programme "Neutron stars - the crust and beyond". After a brief review of the properties, structure, composition and evolution of neutron stars, existing limits to the masses, rotation rates and radii will be summarized. The composition of neutron star crusts will be introduced and constraints obtained from laboratory experiments will be highlighted. Observations of crustal phenomena, such as glitches and magnetar flares, and their potential for structural constraints, will also be discussed.