Dutch labor-leader and politician; born at Amsterdam Feb. 22, 1868. Till his thirteenth year he attended the school conducted by Halberstadt, a well-known teacher of Jewish middle-class boys, and afterward learned from his uncle the trade of diamond-cutting. In 1887 and 1888 and again in 1889 and 1890 he lived in London, where he became interested in socialism. Returning to Holland, he became attached to the Sociaal Democratische Bond, which he left in 1893 on account of its anarchistic principles. With Troelstra and Van der Goes he founded the periodical "De Nieuwe Tijd." In 1894 he became one of the twelve founders of the Sociaal Democratische Arbeiders Partij (S. D. A. P.); in 1898 he became a member of its committee; and since 1900 he has been its chairman.
On Nov. 7, 1894, on the occasion of a strike in the Dutch navy-yards, a confederation was formed of different parties, with a central committee of which Polak was chosen chairman. In Jan., 1895, he was appointed chairman of the Algemeene Nederlandsche Diamantbewerkers Bond (A. N. D. B.), which union had its origin in that strike. Since then he has been editor-in-chief of the "Weekblad." Polak gave up his trade of diamond-cutting and devoted himself to the organization of the A. N. D. B., which is considered the greatest and best-organized union in the Netherlands. Besides many minor strikes Polak has directed seven important ones, and has succeeded in obtaining: (1) the abolition of thetruck system; (2) an advance of the rate of wages from 50 to 200 per cent; and (3) the shortening of the working-day from twelve to nine hours. The A. N. D. B. strives to raise the moral and intellectual status of its members by arranging lecture courses and by maintaining a library. It includes nine sections of the diamond industry, with a membership of 7,500—4,500 Jews and 3,000 Christians. It is without any political tendency; and since 1900 it has had a building of its own, and its own printing-office with twenty-five employees.
Polak is a member of the committee for statistics (since 1900), chairman of the Kamer van Arbeid (since 1900), member of the municipality (since 1902), and chairman of the Alliance Universelle des Ouvriers Diamantaires (since 1903). He has a great predilection for history. Besides some brochures for socialistic propaganda Polak has translated S. and B. Webb's "History of Trade Union" ("Geschiedenis van het Britsche Vereenigingsleven," Amsterdam, 1900) and "Theorie en Praktijk van het Britsche Vereenigingsleven," ib. 1902. He is correspondent of the "Clarion," "Neue Zeit," "Mouvement Socialiste," and other papers.