The International Socialist Bureau was established in 1900 as the administrative body of the Second International, which aimed to unite socialist parties worldwide. Its primary function was to coordinate activities, share information, and promote socialist principles among member parties. The Bureau played a crucial role in organizing international socialist congresses and fostering collaboration among various socialist movements. The Bureau was instrumental in addressing issues such as workers' rights and anti-imperialism. However, it faced challenges during World War I, leading to a decline in its influence. Eventually, the Bureau was dissolved in 1940, marking the end of its significant role in the international socialist movement.