I will speak about Bose-Einstein condensation in quantum magnets, inparticular the compound NiCl2-4SC(NH2)2. Here a magnetic field-inducedquantum phase transition into XY antiferromagnetism can be mapped onto BECof the spin system due to the uniaxial symmetry of the spin environment. Thetuning parameter for BEC transition is the magnetic field rather than thetemperature. Some interesting phenomena arise, for example the fact that themass of the bosons that condense can be strongly renormalized by quantumfluctuations. I will discuss the theory and experimental evidence we havegathered for the last six years, and finally the utility of this mapping forboth understanding the nature of the quantum magnetism and testing thethermodynamic limit of Bose-Einstein Condensation.