Context:

Explicitly mentioned as 'his book' published in 1900, quoted at the beginning of the episode to describe German character

Context:

Described as having 'written a massive, colossal book' arguing that Britain's colonial expansion was merely a means to an end, with the real focus being the balance of power in Central Europe

Context:

Referenced as one of the great romantic works when discussing Coleridge's influence and his time spent learning German philosophy