Known to legions of radio listeners for her exuberant coverage of books and culture, Petra Mayer was a self-described “resident nerd” at NPR. She learned to read at age 3 and was, by her account, an “avid reader” by preschool. She seemed to consume pages not by the word but by the paragraph, and reserved special affection for works of romance, fantasy and science fiction — the genres that snootier readers sniffed at and more self-important critics disdained.