The document discusses the need for a semantic book search engine that can leverage the structural semantics and logical connections within books. Existing search techniques treat books as plain text collections, resulting in inaccurate search results. A semantic book search engine would connect books in a graph-like structure using comprehensive book structure ontologies and domain-level ontologies. This would enable better book searching, ranking, recommendations, and fine-grained access to internal book elements like tables, figures, and passages.