Toynbee examines the modern world from the perspective of societies confronted by the expansion of Western power. He traces encounters with Russia, the Islamic world, India and East Asia, considering how military pressure, colonial rule, technology and Western political ideas prompted responses ranging from resistance to selective adoption. He argues that Western influence cannot be understood only as the spread of progress, since many non-Western peoples experienced the West primarily through conquest and political domination.

The later lectures consider the psychology of encounters between civilisations and compare the modern expansion of the West with the earlier influence of the Graeco-Roman world. Toynbee distinguishes the adoption of Western technology and institutions from acceptance of Western culture as a whole, and questions whether Western political predominance will endure. Across the series, he presents relations between civilisations as reciprocal historical processes in which contact can provoke imitation, resistance, nationalism and cultural transformation.