The Meyer/Misch and related models were found to be the most energetically stable for the crystalline structure of cellulose I. The cellobioside structure is the monomer of cellulose I because structures having cellobiose as monomer have proven to be energetically much less stable. The conformation of the monomers terminating the crystalline zone and initiating the amorphous zone have been accurately described. The cause and mechanism of termination of the crystalline zone have been identified and described. A few new considerations regarding the conformation and appearance of the amorphous zones in cellulose I, in which the chains are in helicoidal conformations, are discussed. The predominance of van der Wads and H-bond interactions in the crystalline zone have been confirmed, and the H-bond values, locations, and distribution in the crystalline zone have been accurately mapped.