Historically, the need to carry out large numbers of complex calculations in a sequential manner, in order to undertake sufficient sampling to produce meaningful results, has limited the size of a system that could be reasonably modeled to hundreds of atoms in the 1980s, to millions of atoms now. That limit will continue to be pushed larger but there are new problems associated with systems of even hundreds of thousand atoms. The state-of-the-art computational methods are only now at the point that the smallest cellulosic systems found in nature, such as the plant cell wall cellulose microfibril, can be modeled with confidence. Together with the current force field development, computer hardware technology, and numerical methodologies for high performance computing, the stage is set to probe cellulose and its structures and reactions and answer questions that have been as recalcitrant as the cellulose itself. Reported modeling studies of the cellulose preparations (37, 50-57) are among the few examples of computational structural studies of cellulose. However, Nimlos and coworkers (58) have recently shown that MD simulations of protein-cellulose interactions can shed light on the as yet unknown nature of those interactions. Beyond simple MD simulations, we will discuss the kinds of numerical simulations and the properties that can be studied, quantified, and predicted.