This paper attempts to familiarize readers with all segments of the Second International, from its ambitious beginnings and foundation in the year 1889 to its sorrowful ending and collapse in the year 1914. In the first part, the legacy of the First International, the Parise Commune and generally of socialism and workers movements, which the Second international embraced in its programme, is highlighted. Afterwards, what is considered is, through relations between socialist parties and trade unions of different countries, the question of how this new international socialist movement is organized. The paper also explains the theoretical foundations of the Second International, which are mostly taken from marxism. It attempts to show the actions of the Second International, as much precisely as possible, which were agreed upon the congresses, which were held every 2 – 4 years. The main ideas and goals of the Second Intrernational are discussed. The paper views how much and what kind of efforts the Second International has used in order to change the course of history. Emphasis is put on problems which were present through the whole existence of the Second International. In addition, the paper examines how much the circumstances of time and place, and phenomena characteristic for that period, such as nationalism, imperialism and militarism, have affected on divisions in the socialist movement.