He was born on 19 September 1893 in Vilnius and attended the local grammar school. After finishing the school in 1912, he started legal studies at the University of St. Petersburg where he continued to be active in the Progressive and Independent Youth Union which he had joined in his grammar school days; he was also the editor of Głos Młodych [“Voice of the Youth”]. In 1914, he joined the Polish Socialist Party and in 1916 he was elected to its leadership. During World War I, he worked at the Central Academic Society and at the Social Work Office in Warsaw and was still engaged in underground activities. In mid-1917, he became the editor-in-chief of Robotnik [“The Worker”], which was published by the Polish Socialist Party (PPS). He resigned after 18 months when he was elected to the Sejm (lower chamber of the Polish Parliament); in the Sejm, he served uninterruptedly until 1935. From 1919 to 1929, he edited Przedświt [“The Dawn”], in 1920 he was the editor of Trybuna [“Tribune”] and from 1927 to 1939 of Robotnik. In 1926, he published his Teoria i praktyka socjalizmu wobec nowych zagadnień [“Theory and practice of socialism in the face of new issues”], which is regarded as the most important work presenting the interwar doctrine of Polish socialists; he penned many resolutions and the PPS programme of 1937 as well as two draft constitutions for the Republic of Poland (1919, 1929). He wrote Izby wyższe w parlamentach współczesnych [“Upper chambers in contemporary parliaments”] and Demokracja parlamentarna w Polsce [“Parliamentary democracy in Poland”], but above all published texts on socialist policy (O co walczy Polska Partia Socjalistyczna? [“What is the Polish Socialist Party fighting for?”]). When World War II broke out, he took part in the defence of Warsaw and was among the co-founders of the Service for Poland’s Victory resistance movement. In December 1939, he was arrested by the Gestapo and was executed in Palmiry on 21 June 1940.