German intellectual history of the last 300 years is an integral part of the history of Europe. As with its Scottish counterpart, the early Enlightenment in Germany followed the natural law tradition inspired by Roman philosophers such as Cicero, as shown by Benjamin Straumann in his recent Roman Law in the State of Nature (2015). Early modern natural law aimed to provide a political and moral framework that would be universally valid, despite the confessional division that had plunged Europe into endless civil and religious wars. Germany, where the Protestant Reformation had been born, had to face this predicament in even more radical terms than other countries. Tim Hochstrasser's Natural Law Theories in the Early Enlightenment (2000) gives a comprehensive account of this period.

Christian Thomasius (1655-1728) was a key player in subsequent developments. His legacy is now mainly seen in his struggle for toleration, but in the 18th century his writings on jurisprudence were taught in the leading Protestant law faculties in Germany, as outlined by Thomasius in Essays on Church, State and Politics (2007), edited by Ian Hunter, Thomas Ahnert and Frank Grunert. In his Rival Enlightenments (2001) Ian Hunter charts the wider intellectual context of this development, showing the rivalry between the doctrines of Thomasius and the illustrious Gottfried Wilhelm Leibniz (1646-1716). Germany and Austria were united in the Holy Roman Empire, an elective monarchy with a federal structure, which embraced much of central Europe. At the same time, German territorial states (such as Saxony, Bavaria and Brandenburg) increasingly claimed their political sovereignty within this framework. A delicate balance between different confessional and political claims had to be found between these alternatives. With Thomasius, who advocated the political and confessional independence of the territorial state, and Leibniz, who wanted to strengthen the political structures of the empire, we have the crucial watershed from the Baroque period to new Enlightenment philosophy.

The Anglophone world is perhaps more familiar with the work of Immanuel Kant, Gotthold Ephraim Lessing, Moses Mendelssohnn, Johann Wolfgang von Goethe, Friedrich Schiller and Johann Gottlieb Fichte, the intellectual giants of the 18th century. They forcefully argued for religious toleration and the need for education, including of the lower classes. According to Kant, the motto of Enlightenment was 'sapere aude! Have the courage to make use of your own understanding!' Individual autonomy and emancipation from prejudice were the main concerns of these distinguished thinkers, as shown by Frederick Beiser in Diotima's Children: German Aesthetic Rationalism from Leibniz to Lessing (2009) and The Fate of Reason (1987), and Terry Pinkard, German Philosophy 1760-1860 (2002). Influenced by Montesquieu's Spirit of the Laws (1748), Johann Gottfried Herder (1744-1803) tried to formulate what he believed to be specific about German culture. In contrast, Hegel (1770-1831) pushed German Idealism to a new height; he was probably the last philosopher to attempt a comprehensive and systematic philosophy of all existing phenomena. This included searching for new foundations for a universal philosophy of right. His Phenomenology of the Spirit (1807) proved to be one of the most influential and lasting legacies of the 20th century, in particular for French existentialism, as traced by Martin Schuster in his Autonomy after Auschwitz: Adorno, German Idealism, and Modernity (2014).

With the upheavals of the French Revolution and the Napoleonic Wars, the Holy Roman Empire was dissolved in 1806. At the Congress of Vienna (1814-15), Europe re-established its political order on the old principles, but Austria and Germany went politically separate ways, as highlighted by Brian E. Vick, The Congress of Vienna: Power and Politics after Napoleon (2014). In Germany, Romanticism shaped the first half of the 19th century but, like no other philosophers before them, Marx (1818-83) and Nietzsche (1844-1900) challenged in very different ways the familiar intellectual world of their day. Marx's criticism of existing social injustice led him to declare class war against the bourgeoisie. His determinism and materialism were inspired by his critical reading of Hegel. Nietzsche, in contrast, wanted to liberate the human conscience from the slave morality of Christianity, as he put it in polemical and unambiguous terms. Social and psychological questions began to emerge as newly articulated problems of human society and individuality. Arguably, this is when we can discern the advent of modernity in intellectual history, demonstrated by Francis Wheen in Karl Marx (1999) and Walter Kaufmann in Nietzsche: Philosopher, Psychologist, Antichrist (1974).

As has been studied exhaustively, the 'long 19th century' came to an abrupt end with the First World War. Less well known is how the loss of German colonies impacted on the self-image of the defeated nation, as recently studied by Britta Schilling in Post-Colonial Germany (2014). After the Great War, Germany's Weimar Republic found itself in a precarious internal struggle for political survival against the threats of Communists and Nazis. However, its short, 14-year existence saw one of the most fertile intellectual periods in German history, as discussed by Peter Gay in Weimar Culture: The Outsider as Insider (1968) and more recently in a highly original study by Uri Greenberg, The Weimar Century (2014), in which fascinating case studies show how many 'dominant Cold War concepts embraced by Americans were coined by Germans years before the global conflict with the Soviet Union had begun'. In the build-up to the Second World War, the racial and political fanaticism of the Third Reich drove many German, often Jewish, intellectuals into exile. Hannah Arendt and Leo Strauss, who later became leading political philosophers in the US, were among those forced to leave their country, as shown by Liisi Keedus in The Crisis of German Historicism (2015). The shadow of Nazism loomed large, with sympathisers even in the higher echelons of the British establishment, as Karina Urbach has shown in Go-Betweens for Hitler (2015).

For a single book which engages magisterially with the intellectual landscape outlined here, see Peter Watson, The German Genius: Europe's Third Renaissance (2010), in which he traces how it 'shaped our lives more than we know … was devastated by Hitler but … has lived on'. Indeed, in ways which have yet to be fully appreciated, the German contribution to intellectual life has shaped the cultures and institutions of modern Europe, Britain and the United States. To engage with German intellectual history is to plunge deep into our shared history.

Peter Schröder is a senior lecturer with a particular interest in the history of ideas at University College London.