This report addresses the suitability of the EPUB format for archival preservation. Chapter 2 gives a brief introduction to EPUB. It presents a simple example that illustrates the general structure of an EPUB file. Chapters 3 and 4 go more in-depth, focusing on Core Media Types and the Package and Navigation Documents. Chapter 5 discusses the functionality that is provided by EPUB. In particular, it covers layout and appearance, and the support for multimedia and scripting. For each of these aspects it also explains the differences that exist between versions 2 and 3 of the format. Processing EPUB in an operational (pre-)ingest workflow requires software tools that are able to provide information about each file object (characterisation). Chapter 6 reviews the main available tools. It also includes some tests on 3 data sets. Chapter 7 reviews the overall suitability of EPUB as a preservation format. This is done by evaluating the format against a set of widely used criteria (adapted from The National Archives and Library of Congress). Finally, Chapter 8 wraps up the main conclusions, and provides some recommendations.