Conventional methods of crystal structure determination yield the unit cell structure averaged over space and time. Here we review three different types of fundamental NMR experiments which allow for the determination of the local atomic structure in: i) incommensurate ferroelectrics, ii) hydrogenbonded order-disorder-type ferroelectrics, iii) deuteron glasses.It is shown that NMR can be used to determine the soliton density in incommensurate systems and allows for a direct observation of the intra H-bond proton and deuteron motion. It also allows for the determination of the Edwards-Anderson order parameter in glasses.