By contrast, even Lenin’s wooden tome The Development of Capitalism in Russia constitutes some species of analysis and anatomy, of a kind that would be merely ridiculous to compare with the ravings of Mein Kampf. And from the many Marxists who took issue with Lenin, there proceeded a number of works of a high order of seriousness, and failing to scrutinize them would severely limit one’s knowledge of modern history. To me, the most brilliant—and the most engaging—of these Marxist intellectuals was Rosa Luxemburg, the Polish-born Jew who was the most charismatic figure in the German Social Democratic Party (SPD).

Bertrand Russell’s first book (evolved from a series of lectures he gave in 1896) was on the character of this historic party. Wedded to a rather formalist Marxism in theory, the party in practice provided millions of workers and their families with something like an alternative society within Germany: not merely trade unions but welfare associations, educational institutions, holiday camps, and women’s associations. Strongly critical of Prussian militarism, it felt confident enough in 1912 to declare that in the event of war, it would call for strikes and protests, and endeavor to make alliances with fraternal parties in the other combatant nations. In the event, war hysteria proved so damnably potent that the majority of the Socialist International capitulated in August 1914 and voted to take part in the greatest fratricide the world had ever seen. (Lenin was so shocked by this that he at first refused to believe that the SPD had in fact deserted its position.) Luxemburg was one of the few of the party’s leaders to maintain a stance against the kaiser, and was imprisoned as a consequence. The central tranche of this collection of her letters was written during that bleak incarceration, and that great political relapse. The confusion of the moment is caught in a letter from October 1914, in which she urgently seeks instruction on the best manner of forwarding information by way of Benito Mussolini, entirely unaware that this hitherto anti-war socialist editor had deserted the cause and begun his long swing to the fanatical right.

Slightly lamed since childhood, married only to gain the formalities of citizenship, and famous for the scornfulness of her polemics, Luxemburg was easy to portray as a thwarted and unfeminine personage. But her correspondence shows her to have been an active and ardent lover, as well as a woman constantly distracted from politics by her humanism and her love for nature and literature. In a single letter to her inamorato Hans Diefenbach (whose life was to be thrown away on the western front), written from a Breslau jail in the summer of 1917, there are tender and remorseful reflections on the deaths of parents; some crisp appraisals of the style of Romain Rolland; a recommendation that Diefenbach read Hauptmann’s The Fool in Christ, Emanuel Quint; and some extended observations on the ingenious habits of wasps and birds, as observed through the windows of her cell. Another letter to him earlier in the same year is saturated with their common addiction to the works of Goethe and Schiller, and goes on to offer a spirited hypothesis of a possibly feminist Shakespeare, based on the figure of the unquenchable Rosalind in As You Like It. Her favorite word of opprobrium for the war-makers was barbaric, and it becomes plain that by this she intended no ordinary propaganda slogan, but an intense conviction that European culture itself was being outraged and profaned. She was righter even than she knew.