What book is read during a gurpurb?

During a Gurpurab, Sikhs often read the Guru Granth Sahib, which is the central religious scripture of Sikhism. Specific passages, hymns, or compositions from the Guru Granth Sahib may be recited, reflecting the teachings and principles of the Sikh Gurus. The celebrations typically honor significant events in the lives of the Gurus, such as their births or martyrdoms.