Miss Reillen is the librarian at Franklin High School, where John and Lorraine are students. Since both John and Lorraine have seventh-period study at the library, they see Miss Reillen everyday.
Miss Reillen is called "The Cricket" by the students. John offers an explanation for this nickname in typically unfiltered fashion, saying that Miss Reillen "is a little on the fat side, but that doesn't stop her from wearing these tight skirts which make her nylon stockings rub together when she walks so she makes this scraaaaaaatchy sound", not unlike a cricket. In an irreverent but humorous aside, he adds that "if she taught woodshop or gym, nobody'd really know she makes that sound - but she's the librarian and it's so quiet you can hear every move she makes" (Chapter 1).
Lorraine tempers John's description of Miss Reillen, noting that "she's across the library watching me as I'm typing this, and she's smiling...she's really a very nice woman, though it's true her clothes are too tight, and her nylons do make this scraaaaaaatchy sound when she walks. But she isn't trying to be sexy or anything...she just outgrew her clothes. Maybe she doesn't have any money to buy new ones or get the old ones let out. Who knows what kind of problems she has?" (Chapter 2).