MAXIMALLY RANDOM JAMMING. Packing particles into a container has been important since antiquity, when basketfuls of grain were traded or collected as taxation. Packing applies not just to grains of wheat of course, but also to ball bearings, living cells, a variety of granular media, and the placement of atoms and molecules in solids and liquids. Hence packing has become a science, and the maximum fraction of space that can be filled with spheres is a conjectured 74%. This is for an ordered "face-centered cubic" array that looks like a stack of cannonballs or oranges. (Kepler came very close to the 74% figure four centuries ago.) The mathematics for estimating the maximum filling fraction for an array of disordered, or randomly packed, balls is much more slippery. Salvatore Torquato and his colleagues at Princeton consider that the whole problem of random close packing (RCP) is ill posed and have proposed in its place a new concept which they call maximally random jamming, a precisely defined condition in which spheres are deployed in the most disordered way. Computer simulations show that the packing fraction for the maximally jammed state is about 64%. Torquato (torquato@matter.princeton.edu, 609-258-3341) believes that the new model will help to study randomness in many-body systems in general. (Torquato, Truskett, Debenedetti, Physical Review Letters, 6 March; see figure at Physics News Graphics, also see Select Article.)