Paramagnetic probes present outstanding opportunities for structural biology studies by nuclear magnetic resonance (NMR) spectroscopy. In particular, pseudocontact shifts (PCS) from lanthanide labeled proteins provide unique long-range restraints that help to define the structures of proteins, protein-protein complexes, and protein-ligand complexes [1,2]. The value of PCSs will be illustrated with a range of applications, including resonance assignments and structure determinations of proteins and protein-ligand complexes, and the merits of different paramagnetic tags will be discussed [3, 4].