Cellulose is one of the most important natural raw materials and has been extensively used for more than 100 years in the form of paper and board materials, textiles, a large range of various cellulose derivatives, and many other applications. Over the past 15 years, fundamental research on novel cellulosic types has matured into several new fields of material and product development, which combine the outstanding properties of the natural product cellulose with the specific features of nanomaterials. Like other nanomaterials, these nanocelluloses are characterized by having at least one dimension in the nanometer range. The field of nanocellulosic materials is subdivided into three areas that differ significantly in terms of starting material, production method, and product properties. The members of the nanocellulose family are cellulose nanofibers (CNF), cellulose nanocrystals (CNC), and bacterial nanocellulose (BNC). The last one forms cellulose nano networks.