A method, apparatus and computer program product for navigating in a multi-dimensional space containing an electronic publication formed from predefined portions of text-based data encoded using a markup language are disclosed. A selected predefined portion is displayed in a first display region. A point on a primary axis of the multi-dimensional space corresponding to the displayed pre-defined portion is also displayed. Also, a method, apparatus and computer program product for publishing an electronic publication formed from predefined portions of text-based data encoded using a markup language are also disclosed. Predefined portions are stored in terminal nodes. Higher level nodes are provided for organising the terminal nodes into an hierarchical structure embodied in said electronic publication. Each higher level node contains the identity of a parent node, a position indicator for the higher level node and an associated identifier.