St. Louis-based Classroom Library Co., a six-month old educational distributor and publisher for books for grades K-8, is already finding a niche through its Book Retriever app launched last month. The app, which hit #4 on the iTunes list of paid education apps when it was initially released, is still hovering in the top 25 even though school is out for the summer.

Book Retriever builds on the expertise of Classroom Library founders Benjamin Conn, who also founded and owned school book distributor Knowledge Industries Inc., and his wife, Marla Conn, a reading specialist who has leveled books for many children’s publishers. Parents can use it to scan a book’s ISBN bar code and find out if it’s the right reading level for their child. Teachers can use it to determine what students should read next. The database of leveling information is patent pending and incorporates four different leveling systems across the country.

The app, which has a 136,000 title database, debuted at IRA in Chicago, where, says Benjamin (who continues to update it almost weekly) “it went through the roof. Other people have different apps that you can use to catalog your books. This is meant for parents and teachers.” In addition to the scanning function, Book Retriever contains a “hot list” of 10 books that change monthly that parents and teachers might be especially interested in. This month’s list includes The Hunger Games, several titles by Rick Riordan, Seriously Scary Poems by John Foster, Eve Bunting’s The Wednesday Surprise, and Miss Bindergarden Takes a Field Trip with Kindergarten by Joseph Slate, illustrated by Ashley Wolff. Teachers can use the app to create ISBN barcode labels for their classroom libraries and to keep track of who checked out which titles. Orders placed using the app go directly to Classroom Library, which offers a flat 30% discount.

So far, according to Benjamin, most of the feedback that Classroom Library has gotten has been positive. “The nice thing is that the customers are giving us free product development,” Benjamin says. “They really want to use this as a tool.” Among the difficulties parents have had are how to distinguish what an ISBN is and how to use technology in general. For now, Book Retriever only works for physical books. But that could change with the growing popularity of digital books.