An unstructured book is defined as a set of digital multimedia files called items, together with ordered subsets of them presented to its readers. Thus different readings of the same set of items are possible. Additionally, items may be shown in different versions and languages. The functionality of the software package SPRP used to publish and read such books is described with an overview of what it offers, in a way which should enable readers to further understand the underlying concept and its possible applications but without any details. The software allows the introduction of reader constraints which will prevent them from seeing certain items, as well as protecting the computer files from unauthorized viewing.