  A lot of progress has been made to improve question answering (QA) in recent
years, but the special problem of QA over narrative book stories has not been
explored in-depth. We formulate BookQA as an open-domain QA task given its
similar dependency on evidence retrieval. We further investigate how
state-of-the-art open-domain QA approaches can help BookQA. Besides achieving
state-of-the-art on the NarrativeQA benchmark, our study also reveals the
difficulty of evidence retrieval in books with a wealth of experiments and
analysis - which necessitates future effort on novel solutions for evidence
retrieval in BookQA.
