Only months after the end of World War One, travel brochures were urging American tourists to visit Germany, and many British travellers needed little encouragement to holiday in a country they had been brought up to admire with “its cathedrals.. castles…art treasures..Bach, Beethoven and Wagner.” Since the trench warfare had mostly taken place beyond its borders, German towns were in the main intact, and the landscape “still beautiful and largely unscathed”.

Visitors from abroad were initially surprised by the “civility” and friendliness of the German people: “how can they, outwardly at least, bear so little grudge against the people who have beaten them?” When a sense of betrayal set in, largely against “the Kaiser, their politicians and generals and especially… the Treaty of Versailles” foreign observers often felt some sympathy over its harsh and humiliating terms, likely to prove counterproductive in the longer term, as proved to be the case with the rampant inflation, and the rapid rise of “the chief agitator…a man of low origin”, namely Adolf Hitler.

Even those made incredulous, scornful or uneasy over the Führer’s overwrought rants and grandiose staged appearances and the rapturous mass hysteria which they generated, were impressed by the apparent rapid achievements of his regime, harnessing the innate German efficiency and industry to regenerate the country. Towns were conspicuously clean and well-kept, the Youth Movement encouraged team spirit and a healthy love of nature in the rising generation, and transport was transformed by the construction of at first underused “autobahns” far in advance of say, the British motorway system.

Others were quick to see the potential danger of the underlying fascist nationalism, in some ways hard to distinguish from the authoritarian communism to which it was fiercely opposed – until the brief notorious pact with Russia when it suited the Nazis. Some travellers were blind to the growing persecution of the Jewish population, perhaps in part because anti-Semitism was quite strong in their home countries at the time, but as laws were passed to deprive Jews progressively of their jobs and rights, anger and revulsion against Hitler’s government took root.

Some like the French author Jacques Chardonne were carried away by an utterly distorted view of the “moral beauty” of German society: “courage, will, self-denial, decency and various forms of health”. He even had a romantic view of the SS as “militant monks…. they do not seem to feel sorrow, or fear, or hunger or desire: they are the angels of war come down for a moment from the heaven of Niflheim (in Norse mythology) to help people to perform a task that is too difficult for them”. More pragmatic visitors could see how, by late 1941, physical conditions for ordinary Germans had often deteriorated to the point of making life not worth living.

Yet right to the outbreak of war, people who should have known better failed to take a stand. Even an elderly Lloyd George, flattered during a meeting by Hitler’s praise for his statesmanship in World War One, returned home to shower him with fulsome praise: “a magnetic, dynamic personality…the George Washington of Germany who won independence from his country’s oppressors, while remaining unquestionably a man of peace”. Also, despite avoiding the risk of sitting with Hitler in the Wagner box at the Bayreuth Festival, the conductor Sir Thomas Beecham could not resist the temptation to show off his new London Philharmonic Orchestra in Germany, all expenses paid, as the price of a PR campaign by the Germans to gain acceptance.

This meticulously researched and very readable book creates a vivid sense of life in Germany in the two decades between the World Wars, giving great insight into the causes and effects of the fateful Third Reich. Since it can be hard to keep track of the vast and varied cast of letter and diary writers, it is worth referring to the glossary of characters supplied at the back.

The final brief chapters covering the war itself inevitably rely heavily on the British women who happen to have married Germans. One describes the ludicrous yet poignant irony of an old British friend “dropping by” on his way to “take Kiel” at the end of the war.