Rosa Luxemburg holds an enduring fascination as a radical socialist committed to democratic values, and a woman whose charismatic personality and impassioned speeches inspired her followers without resort to bureaucratic organization. Her assistant and friend, Mathilde Jacob, was Luxemburg's mainstay during her years of imprisonment in World War I. Jacob provided material and emotional support, organized Rosa Luxemburg's clandestine communication with the outside world, and herself played a key role in the illegal work of the Spartacus group. When revolution broke out in Germany in 1918, she sought unsuccessfully to pretect Rosa in the tragic events that led to her death. Mathilde Jacob's memoir, written as a testimony of "love for a person and for a cause", and sent abroad for safe-keeping when she fell victim to the Nazis, was unknown to Rosa Luxembourg's early biographers. It paints a vivd portrait of the subject, and of the group of friends that made up the Spartacus leadership - Karl Liebknecht, Leo Kpgiches, Clara Zetkin and Paul Levi.