Foreword : Book — which pair below carries the same relation and so completes the analogy?

A foreword is the short piece set before a book begins, introducing what is to follow. A prologue does precisely that for a play, being spoken before the action starts. 'Epilogue : Novel' is its mirror, since an epilogue closes the work, and an index likewise sits at the back of a report. 'Chapter : Story' names a portion of the main body itself rather than anything standing in front of it.