We are witnessing a silent revolution in application of the NMR spectroscopy to biological questions. NMR together and X-ray crystallography complement each other in structural studies of proteins and their complexes. I will briefly cover basic principles of NMR relevant for biomolecular studies, quickly moving to examples of handiness of NMR for projects involving proteins and protein interactions with either small or bigger molecules. NMR spectroscopy can not compete with crystallography in speed and straightness but, unlike it, often, using very simple experiments, can answer specific questions about protein interactions with proteins, nucleic acids or drugs. Especially, when it comes to more specific questions and the structure is not the ultimate goal.