Does air have value? In the first volume of Capital, Marx suggested it did not: “A thing can be a use-value, without having value,” he explained. “This is the case whenever its utility to man is not due to labour. Such are air, virgin soil, natural meadows, &c.” Because it has no value, understood by Marx in this context to mean labor value, air cannot be a commodity: “Commodities come into the world in the shape of use-values, articles, or goods, such as iron, linen, corn, &c. This is their plain, homely, bodily form. They are, however, commodities, only because they are something two fold, both object of utility, and, at the same time, depositories of value.” Marx's materialist focus on human labor and industrial production made it hard for him to imagine air as a commodity—at least when he published the first volume of Capital in 1867.

Germany's cooperative movement grew and thrived from its inception in the late 1840s to World War I and beyond. Cooperatives were divided along several lines, and perhaps the most serious point of contention concerned the role of the state in the movement. Cooperative leaders in the two decades before World War I especially debated whether they should accept direct grants and subsidized credit from the Reich and the Länder. The several parts of the cooperative movement construed the question differently; much internecine conflict turned on the answers. The cooperative movement's historiography has largely framed the question as did Hermann Schulze-Delitzsch and other cooperative leaders opposed to state assistance. To him, the issue was whether cooperatives would be based on “self-help” or “state help.”

The Great War is not a historical episode that easily lends itself to studying the subtleties of religious belief systems. Believers on opposite sides claimed that they were engaged in a just war of defense against aggression. They argued that God was on their side, and they prayed for victory of their nation—even if that meant the destruction of their fellow believers who were now considered the enemy. Despite Catholic claims to internationalism and universalism, the overwhelming majority of Catholic bishops and prominent clerics in the public sphere devoted themselves to national causes. Clerical nationalism seemed to overwhelm Christian fellowship, and the clerical nationalist paradigm often served as scholarly shorthand for the experience of religion during the war, especially for long-term studies of Christianity and war. The implacable hostility between French and German Catholic bishops became a convenient symbol of European national enmity in an age of total war.

The year 1924 marked a fundamental turning point in the history of the Weimar Republic. After months of deep crises in 1923, which included foreign occupation, hyperinflation, and attempted coups d'état by both communists and Nazis, the German economy and polity entered a phase of relative stability, and social peace loomed on the horizon. Recognizing the dramatic shift in the sociopolitical landscape, the German Communist Party (Kommunistische Partei Deutschlands, KPD) also underwent a significant transformation. On the political front, the most notable event was the ousting of Ruth Fischer and Arkadij Maslow, under the heavy hand of Moscow, in favor of Ernst Thälmann.

Recent scholarship concerning the Wehrmacht leadership in Nazi Germany's war against the Soviet Union (1941–1945) has provided a much more nuanced picture of the motivation and responsibility of the uppermost strata of general for the brutalization of the conflict. The generals just outside this inner military circle, however, continue to be largely ignored. Questions on the mentality of lower-ranking, frontline commanders toward the war of annihilation and what latitude they reserved for themselves in carrying out orders remain, like the war on the front itself, one of the least researched topics of World War II.