Chemist Jeffrey Long is daring to remake the ubiquitous computer hard drive. Long is devising ways in which chemists can assemble large inorganic molecules packed with different metals to create a host of novel materials for use in the emerging field of nanotechnology. His first target is the molecular magnet, a chemical structure whose electrons can be set spinning in synchrony by a magnetic field. Molecular magnets are a potential replacement for the increasingly crowded metallic films that constitute computer hard drives. Each molecular magnet could represent one bit of memory, enabling storage densities a thousand times greater than those of the best existing films. Long began building his own molecular magnets in 1997, demonstrating a scheme for packing them with progressively more chromium, cobalt and nickel. Unfortunately, his best clusters can only be magnetized at a chilly -270 °C, just 3 °C above absolute zero. Making more practical molecular magnets may take years, but if this field heats up, it could revolutionize computer storage.