The mobile application "BOOK A CHALLENGE" is a multilingual quiz application of the City Library of Subotica, with an educational character. The application offers a "Library Quiz" that communicates information and the most common questions related to the Library's core business. The application is also intended for conducting the prize quiz "I read and skip" that the City Library of Subotica organizes once a year in elementary schools with the aim of encouraging reading among elementary school students.