22. A computer-implemented method of determining an importance score for an entity mentioned in a book, comprising: identifying library classification data indicating a classification of the book; determining whether the library classification data mention entities from the book; assigning query-independent importance scores to the entities of an entity type mentioned in the book, wherein the importance scores of entities mentioned in the library classification data are elevated relative to importance scores of entities not mentioned in the library classification data; selecting a subset of the plurality of entities responsive to the entities' importance scores and entity type; and presenting the selected subset of entities to a user.
25. The method of claim 22 , wherein the book is in a corpus comprising a plurality of books and wherein assigning query-independent importance scores comprises: determining a frequency that an entity is mentioned in the book and a frequency that the entity is mentioned in other books in the corpus; and calculating the importance score for the entity based at least in part on the frequency of which the entity is mentioned in the book and the frequency that the entity is mentioned in other books in the corpus.