Data storage space and access time are significantly decreased by use of an Enhanced MTree data structure, in which data is stored in the nodes of the tree. Two kinds of nodes--predecessor nodes and successor nodes--are coexisting in the data structure and are interrelated by a distribution of pointers. Both types of nodes may be further subdivided into packed nodes and alternate list nodes where the distribution of pointers includes next node pointers in the packed nodes and alternate node pointers in the alternate list nodes. The progressions of nodes are associated with progressions of items of coded data with each of the progressions of nodes associated with at least one identifier. The identifiers give the progression of nodes the ability to locate other progressions of nodes or the ability to be located by another progression of nodes or by an external object.