This document discusses open source software options for public libraries. It defines open source as software that users can freely run, distribute, modify and study. Open source draws on collaboration and peer review to develop accessible code. The document provides examples of open source operating systems like Ubuntu, web browsers like Firefox and Google Chrome, office suites like OpenOffice, and integrated library systems like Koha that are freely available for libraries. It also discusses how the National Library of the Philippines' Open Source Systems for Public Libraries program can help libraries through technology transfers, training, and providing electronic resources.