A librarian at the public library in Evanston, Ill., was recently preparing for a program titled “The Quran: Is It a ‘Good Book’?”

She gathered books to display for attendees and discovered that inside the cover of one, “The Koran for Dummies,” someone had written “lies cover to cover,” drawn a swastika and made a disparaging remark about the Prophet Muhammad.

She discovered six more books about Islam and the Quran that had been similarly defaced with racist language and imagery, officials said. The vandalism was a first for the library, Karen Danczak Lyons, its director, said in an interview.

There has been a spate of hate crimes targeting libraries, their books or patrons, the authorities say — offenses they had rarely seen before. These crimes coincide with a recent report by the F.B.I. that attacks against American Muslims surged last year.