Cellulose is an important biopolymer primarily stored as plant cell wall material. Plant-synthesized cellulose forms elementary fibrils that are micrometers in length and 3-5 nm in dimensions. Cellulose is a dynamic structure, and its size and property vary in different cellulose-containing materials. Atomic force microscopy offers the capability of imaging surface structure at the subnanometer resolution and under nearly physiological conditions, therefore providing an ideal tool for cellulose characterization.